Matthew 18:19-20
"Again I say unto you, That if two of you shall agree on earth as touching any thing that they shall ask, it shall be done for them of my Father which is in heaven.  For where two or three are gathered together in my name, there am I in the midst of them."

Luke 6:28
"Bless them that curse you, and pray for them which despitefully use you."

Romans 8:26
" Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered."

James 5:16
"Confess your faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much."

Psalm 4:3
"But know that the LORD hath set apart him that is godly for himself: the LORD will hear when I call unto him."

Proverbs 15:29
"The LORD is far from the wicked: but he heareth the prayer of the righteous."

Proverbs 28:9
"He that turneth away his ear from hearing the law, even his prayer shall be abomination."

Isaiah 1:15
"And when ye spread forth your hands, I will hide mine eyes from you: yea, when ye make many prayers, I will not hear: your hands are full of blood"

John 9:31
"Now we know that God heareth not sinners: but if any man be a worshipper of God, and doeth his will, him he heareth."

1John 5:14-15
"And this is the confidence that we have in him, that, if we ask any thing according to his will, he heareth us: And if we know that he hear us, whatsoever we ask, we know that we have the petitions that we desired of him."

Psalm 66:18
"If I regard iniquity in my heart, the Lord will not hear me"

Mark 11:25-26
"And when ye stand praying, forgive, if ye have ought against any: that your Father also which is in heaven may forgive you your trespasses.  But if ye do not forgive, neither will your Father which is in heaven forgive your trespasses."

1John 1:9
"If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness."

2Chronicles 20:21-22
"And when he had consulted with the people, he appointed singers unto the LORD, and that should praise the beauty of holiness, as they went out before the army, and to say, Praise the LORD; for his mercy endureth for ever.  And when they began to sing and to praise, the LORD set ambushments against the children of Ammon, Moab, and mount Seir, which were come against Judah; and they were smitten."

Psalm 22:3
"But thou art holy, O thou that inhabitest the praises of Israel."

Psalm 30:12
"To the end that my glory may sing praise to thee, and not be silent. O LORD my God, I will give thanks unto thee for ever."

Psalm 34:1
"I will bless the LORD at all times: his praise shall continually be in my mouth."

Psalm 47:6
"Sing praises to God, sing praises: sing praises unto our King, sing praises."

Psalm 63:4
"Thus will I bless thee while I live: I will lift up my hands in thy name."

Psalm 95:6
"O come, let us worship and bow down: let us kneel before the LORD our maker. "

Psalm 96:4
"For the LORD is great, and greatly to be praised: he is to be feared above all gods."

Psalm 149:6-9
"Let the high praises of God be in their mouth, and a twoedged sword in their hand; to execute vengeance upon the heathen, and punishments upon the people; to bind their kings with chains, and their nobles with fetters of iron; to execute upon them the judgment written: this honour have all his saints. Praise ye the LORD."

Psalm 150:3
"Praise him with the sound of the trumpet: praise him with the psaltery and harp."

Ephesians 5:20
"Giving thanks always for all things unto God and the Father in the name of our Lord Jesus Christ;"

1Thessalonians 5:18
"In every thing give thanks: for this is the will of God in Christ Jesus concerning you."

Psalm 5:3
"My voice shalt thou hear in the morning, O LORD; in the morning will I direct my prayer unto thee, and will look up."

Psalm 19:14
"Let the words of my mouth, and the meditation of my heart, be acceptable in thy sight, O LORD, my strength, and my redeemer."

Psalm 86:6
"Give ear, O LORD, unto my prayer; and attend to the voice of my supplications."

Mark 11:24
"Therefore I say unto you, What things soever ye desire, when ye pray, believe that ye receive them, and ye shall have them."

Matthew 19:26
"But Jesus beheld them, and said unto them, With men this is impossible; but with God all things are possible."

Luke 11:9
"And I say unto you, Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you."

Ephesians 6:18
"Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints"

James 5:16
"Confess your faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much."

1John 3:22
"And whatsoever we ask, we receive of him, because we keep his commandments, and do those things that are pleasing in his sight."

1John 5:14-15
"And this is the confidence that we have in him, that, if we ask any thing according to his will, he heareth us: and if we know that he hear us, whatsoever we ask, we know that we have the petitions that we desired of him."

1Kings 19:12
"And after the earthquake a fire; but the LORD was not in the fire: and after the fire a still small voice."

Psalm 4:4
"Stand in awe, and sin not: commune with your own heart upon your bed, and be still. Selah."

Hebrews 10:19
"Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus"
(where God dwells... He's right there... so listen!)

Hebrews 12:25
"See that ye refuse not him that speaketh. For if they escaped not who refused him that spake on earth, much more shall not we escape, if we turn away from him that speaketh from heaven"

1Samuel 23:2-4
"Therefore David enquired of the LORD, saying, Shall I go and smite these Philistines? And the LORD said unto David, Go, and smite the Philistines, and save Keilah.
And David's men said unto him, Behold, we be afraid here in Judah: how much more then if we come to Keilah against the armies of the Philistines?
Then David enquired of the LORD yet again. And the LORD answered him and said, Arise, go down to Keilah; for I will deliver the Philistines into thine hand."

Judges 6:37-39
"Behold, I will put a fleece of wool in the floor; and if the dew be on the fleece only, and it be dry upon all the earth beside, then shall I know that thou wilt save Israel by mine hand, as thou hast said.  And it was so: for he rose up early on the morrow, and thrust the fleece together, and wringed the dew out of the fleece, a bowl full of water.  And Gideon said unto God, Let not thine anger be hot against me, and I will speak but this once: let me prove, I pray thee, but this once with the fleece; let it now be dry only upon the fleece, and upon all the ground let there be dew."

1Kings 8:54
"And it was so, that when Solomon had made an end of praying all this prayer and supplication unto the LORD, he arose from before the altar of the LORD, from kneeling on his knees with his hands spread up to heaven."

1Kings 8:35, 38, 42, 44, 48
[Pray facing toward Jerusalem]

Psalm 5:3
"My voice shalt thou hear in the morning, O LORD; in the morning will I direct my prayer unto thee, and will look up."

Psalm 27:14
"Wait on the LORD: be of good courage, and he shall strengthen thine heart: wait, I say, on the LORD."

Psalm 37:9
"For evildoers shall be cut off: but those that wait upon the LORD, they shall inherit the earth."

Psalm 40:1
"I waited patiently for the LORD; and he inclined unto me, and heard my cry."

Psalm 62:5
"My soul, wait thou only upon God; for my expectation is from him."

Daniel 10:3, 12-13
"I ate no pleasant bread, neither came flesh nor wine in my mouth, neither did I anoint myself at all, till three whole weeks were fulfilled.
Then said he unto me, Fear not, Daniel: for from the first day that thou didst set thine heart to understand, and to chasten thyself before thy God, thy words were heard, and I am come for thy words.
But the prince of the kingdom of Persia withstood me one and twenty days: but, lo, Michael, one of the chief princes, came to help me; and I remained there with the kings of Persia."
(The prayer had already been answered)

Nehemiah 4:9
"Nevertheless we made our prayer unto our God, and set a watch against them day and night, because of them."
(he prayed as well as took action)

Luke 18:1
"And he spake a parable unto them to this end, that men ought always to pray, and not to faint;"

Romans 12:12
"Rejoicing in hope; patient in tribulation; continuing instant in prayer;"

Ephesians 6:18
"Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;"

Colossians 4:2
"Continue in prayer, and watch in the same with thanksgiving;"

1Thessalonians 5:17
"Pray without ceasing."

1Timothy 4:4-5
"For every creature of God is good, and nothing to be refused, if it be received with thanksgiving: for it is sanctified by the word of God and prayer."
(mealtime prayer)

James 4:3
"Ye ask, and receive not, because ye ask amiss, that ye may consume it upon your lusts."

1John 3:22
"And whatsoever we ask, we receive of him, because we keep his commandments, and do those things that are pleasing in his sight."

2Samuel 5:17-25
But when the Philistines heard that they had anointed David king over Israel, all the Philistines came up to seek David; and David heard of it, and went down to the hold. The Philistines also came and spread themselves in the valley of Rephaim.

And David enquired of the LORD, saying, Shall I go up to the Philistines? wilt thou deliver them into mine hand? And the LORD said unto David, Go up: for I will doubtless deliver the Philistines into thine hand.

And David came to Baal-perazim, and David smote them there, and said, The LORD hath broken forth upon mine enemies before me, as the breach of waters. Therefore he called the name of that place Baal-perazim.  And there they left their images, and David and his men burned them.

And the Philistines came up yet again, and spread themselves in the valley of Rephaim.   And when David enquired of the LORD, he said, Thou shalt not go up; but fetch a compass behind them, and come upon them over against the mulberry trees.  And let it be, when thou hearest the sound of a going in the tops of the mulberry trees, that then thou shalt bestir thyself: for then shall the LORD go out before thee, to smite the host of the Philistines.

And David did so, as the LORD had commanded him; and smote the Philistines from Geba until thou come to Gazer."

Matthew 6:9
"After this manner therefore pray ye: Our Father which art in heaven, Hallowed be thy name."

John 14:13-14
"And whatsoever ye shall ask in my name, that will I do, that the Father may be glorified in the Son.  If ye shall ask any thing in my name, I will do it."

John 15:16
"Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you."

John 16:23
"And in that day ye shall ask me nothing. Verily, verily, I say unto you, Whatsoever ye shall ask the Father in my name, he will give it you."

John 16:26
"At that day ye shall ask in my name: and I say not unto you, that I will pray the Father for you:"

Matthew 11:25-26
"At that time Jesus answered and said, I thank thee, O Father, Lord of heaven and earth, because thou hast hid these things from the wise and prudent, and hast revealed them unto babes.  Even so, Father: for so it seemed good in thy sight."

Mark 6:46
"Blessed are they which do hunger and thirst after righteousness: for they shall be filled."

Luke 3:21
 Now when all the people were baptized, it came to pass, that Jesus also being baptized, and praying, the heaven was opened,"

Luke 5:16
And he withdrew himself into the wilderness, and prayed."

Luke 6:12
And it came to pass in those days, that he went out into a mountain to pray, and continued all night in prayer to God."

Luke 9:18
And it came to pass, as he was alone praying, his disciples were with him: and he asked them, saying, Whom say the people that I am?"

Luke 9:28
And it came to pass about an eight days after these sayings, he took Peter and John and James, and went up into a mountain to pray."

John 17:11
And now I am no more in the world, but these are in the world, and I come to thee. Holy Father, keep through thine own name those whom thou hast given me, that they may be one, as we are."

John 17:25
O righteous Father, the world hath not known thee: but I have known thee, and these have known that thou hast sent me."

Genesis 24:45
"And before I had done speaking in mine heart...."

Jesus prayed out loud in Matthew 26:39,42, 44; Mark 14:35, 39; Luke 22:41-42; John 17:1-26

Luke 18:10-14
"Two men went up into the temple to pray; the one a Pharisee, and the other a publican.
The Pharisee stood and prayed thus with himself, God, I thank thee, that I am not as other men are, extortioners, unjust, adulterers, or even as this publican.  I fast twice in the week, I give tithes of all that I possess.
And the publican, standing afar off, would not lift up so much as his eyes unto heaven, but smote upon his breast, saying, God be merciful to me a sinner.
I tell you, this man went down to his house justified rather than the other: for every one that exalteth himself shall be abased; and he that humbleth himself shall be exalted."
(they both prayed out loud.  Should Jesus have commented on staying quiet if that was important?)

I've heard people say that they don't pray out loud because they don't want satan to hear them.  Yet, those same people probably believe that satan can put thoughts inside their heads.

The scriptures don't specifically say satan (and angels) can or cannot hear our thoughts.  Yet, in Daniel 10:7 Daniel heard and saw things  and a spiritual being that others did not.  So, that seems to indicate that it all was done by thought processes.

Joseph heard from an angel in his dreams in Matthew 1:20.  In Acts 10:3 Cornelius saw and heard an angel in a vision.

If satan and his demons cannot read our thoughts then we can probably assume they also cannot transmit thoughts into our heads.  That means that whenever we hear a "still, small voice" then we will always think it is God's voice.  I know I cannot believe all communication I receive is only from God.

What did Paul infer in 2Corinthians 11:3 "But I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so your minds should be corrupted from the simplicity that is in Christ"?

I firmly believe that some fortune tellers, witches, psychics, and the like get at least some of their information from the demonic realm.  Ask one of them how it is communicated.  What does it mean "familiar spirits" in Isaiah 19:3?  Take a look at 1Samuel 28:7-20.

I wouldn't be so sure that the demonic realm cannot hear our thoughts if I were you.

Matthew 6:7
 "But when ye pray, use not vain repetitions, as the heathen do: for they think that they shall be heard for their much speaking."

That sounds like just repeating and repeating with the mouth and not the heart. For example:  there are churches that repeat words of prayer either by memory, repeating what someone tells them to say, or reading out of a book. That is praying hoping to be heard just because they are speaking.