Mark 2:8

And Jesus, knowing afterward in his spirit that they so reasoned within themselves, said unto them, Why think ye these things in your hearts?

1 Chronicles 29:17

I know also, my God, that thou dost try the heart, and hast pleasure in uprightness. As for me, in the uprightness of my heart I have willingly offered all these things; and now have I seen with joy that thy people, who are present here, have given willingly unto thee.

Psalm 139:2

Thou knowest my sitting down and my rising up, thou dost understand my thoughts from afar.

Proverbs 15:26

The thoughts of the wicked are an abomination to the LORD, but the speech of the pure is pure.

Proverbs 24:9

The thought of the foolish is sin, and the scorner is an abomination to men.

Isaiah 55:7

Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto the LORD, and he will have mercy upon him; and to our God, for he will abundantly pardon.

Ezekiel 38:10

Thus hath the Lord GOD said: It shall also come to pass in that day, that words shall rise up in thy heart, and thou shalt conceive an evil thought:

Matthew 9:4

And Jesus knowing their thoughts said, Why think ye evil in your hearts?

Mark 7:21

For from within, out of the heart of men, come forth the evil thoughts, the adulteries, the fornications, the murders,

Luke 5:22

Then Jesus, knowing their thoughts and answering them said, What reason ye in your hearts?

Luke 6:8

But he knew their thoughts and said to the man who had the withered hand, Rise up and stand forth in the midst. And he arose and stood forth.

Luke 7:39-40

Now when the Pharisee who had invited him saw it, he spoke within himself, saying, This man, if he were a prophet, would have known who and what manner of woman this is that touches him, for she is a sinner.

Luke 24:38

And he said unto them, Why are ye troubled? and why do thoughts arise in your hearts?

John 2:24-25

But Jesus did not trust himself unto them because he knew all men

John 6:64

But there are some of you that do not believe. For Jesus knew from the beginning who they were that did not believe and who should betray him.

John 21:17

He said unto him the third time, Simon, son of Jonas, lovest thou me? Peter was grieved because he said unto him the third time, Lovest thou me? And he said, Lord, thou knowest all things; thou knowest that I love thee. Jesus said unto him, Feed my sheep.

Acts 5:3

But Peter said, Ananias, why has Satan filled thy heart to lie to the Holy Spirit and to defraud of the price of the land?

Acts 8:22

Repent therefore of this thy wickedness and pray God, if perhaps this thought of thine heart may be forgiven thee.

Hebrews 4:13

Neither is there any created thing that is not manifested in his presence, but all things are naked and opened unto the eyes of him of whom we speak.

Revelation 2:23

And I will kill her children with death, and all the congregations shall know that I AM he that searches the kidneys and hearts, and I will give unto each one of you according to your works.

Treasury of Scripture Knowledge

Summary

And immediately when Jesus perceived in his spirit that they so reasoned within themselves, he said unto them, Why reason ye these things in your hearts?

General references

Bible References

When

1 Chronicles 29:17
I know also, my God, that thou dost try the heart, and hast pleasure in uprightness. As for me, in the uprightness of my heart I have willingly offered all these things; and now have I seen with joy that thy people, who are present here, have given willingly unto thee.
Matthew 9:4
And Jesus knowing their thoughts said, Why think ye evil in your hearts?
Luke 5:22
Then Jesus, knowing their thoughts and answering them said, What reason ye in your hearts?
Luke 6:8
But he knew their thoughts and said to the man who had the withered hand, Rise up and stand forth in the midst. And he arose and stood forth.
Luke 7:39
Now when the Pharisee who had invited him saw it, he spoke within himself, saying, This man, if he were a prophet, would have known who and what manner of woman this is that touches him, for she is a sinner.
John 2:24
But Jesus did not trust himself unto them because he knew all men
John 6:64
But there are some of you that do not believe. For Jesus knew from the beginning who they were that did not believe and who should betray him.
John 21:17
He said unto him the third time, Simon, son of Jonas, lovest thou me? Peter was grieved because he said unto him the third time, Lovest thou me? And he said, Lord, thou knowest all things; thou knowest that I love thee. Jesus said unto him, Feed my sheep.
Hebrews 4:13
Neither is there any created thing that is not manifested in his presence, but all things are naked and opened unto the eyes of him of whom we speak.
Revelation 2:23
And I will kill her children with death, and all the congregations shall know that I AM he that searches the kidneys and hearts, and I will give unto each one of you according to your works.

Why

Mark 7:21
For from within, out of the heart of men, come forth the evil thoughts, the adulteries, the fornications, the murders,
Psalm 139:2
Thou knowest my sitting down and my rising up, thou dost understand my thoughts from afar.
Proverbs 15:26
The thoughts of the wicked are an abomination to the LORD, but the speech of the pure is pure.
Proverbs 24:9
The thought of the foolish is sin, and the scorner is an abomination to men.
Isaiah 55:7
Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto the LORD, and he will have mercy upon him; and to our God, for he will abundantly pardon.
Ezekiel 38:10
Thus hath the Lord GOD said: It shall also come to pass in that day, that words shall rise up in thy heart, and thou shalt conceive an evil thought:
Luke 24:38
And he said unto them, Why are ye troubled? and why do thoughts arise in your hearts?
Acts 5:3
But Peter said, Ananias, why has Satan filled thy heart to lie to the Holy Spirit and to defraud of the price of the land?
Acts 8:22
Repent therefore of this thy wickedness and pray God, if perhaps this thought of thine heart may be forgiven thee.

General references

John 20:23
unto those whose sins ye release, they shall be released; and unto those whose sins ye retain, they shall be retained.