Mark 2:8

And immediately Jesus perceived in His spirit what they were reasoning in their minds and said to them, "Why are you reasoning like this in your minds?

Matthew 9:4

Knowing what they were thinking, Jesus said, "Why are you having such evil thoughts in your minds?

Mark 7:21

For from within, out of people's hearts, proceed evil thoughts, sexual immorality, stealing, murder, extramarital affairs,

Luke 5:22

But Jesus perceived their reasonings and answered them, "Why are you reasoning in your hearts?

Luke 6:8

But He knew what they were thinking. Then He said to the man with the deformed hand, "Get up, step forward in front of everyone." So, he got up and stepped forward.

Luke 7:39-40

Now when the Pharisee who had invited Jesus saw this, he said to himself, "If this man were a prophet, he would have known who touched him and what kind of a woman she was --- a sinner."

Luke 24:38

Then Jesus said to them, "Why are you [so] upset? And why are you having doubts [about me] in your minds?

John 2:24-25

But Jesus would not trust Himself to them [i.e., to the care of these Jewish leaders] because He knew all men,

John 6:64

But there are some of you who do not believe [in me]." For Jesus knew from the beginning which ones would not believe [in Him] and which one would turn Him over [i.e., to the Jewish authorities].

John 21:17

Then Jesus asked him a third time, "Simon, son of John, do you [truly] love me?" Peter was sad because Jesus had asked him a third time, "Do you [even] love me?" So, he said to Jesus, "Lord, you know all things. You [surely] know that I love you." Jesus replied to him, "[Then] feed my sheep.

Acts 5:3

But Peter said to Ananias, "Why has Satan filled your heart [causing you] to deceive the Holy Spirit by keeping back part of the selling price of the land [while representing it as the full price]?

Acts 8:22

So, repent [i.e., change your heart and life] of such a terrible thing and pray for the Lord to forgive you for even thinking of such a thing. Perhaps He will [if you are really sincere].

Hebrews 4:13

And no created being is hidden from God's sight, but everything is laid bare and is openly visible to the eyes of God, to whom we must give account.

Revelation 2:23

And I will strike her children dead [or, "kill her children by some terrible calamity" See Ex. 5:3 LXX]. Then all the churches will know that I am the One who searches the inmost being of people [Note: The Greek says, "searches the kidneys and hearts." In that day these internal organs stood for the inner thoughts, emotions, etc.]. And I will repay each one of you people according to what you have done.

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

Matthew 9:4
Knowing what they were thinking, Jesus said, "Why are you having such evil thoughts in your minds?
Luke 5:22
But Jesus perceived their reasonings and answered them, "Why are you reasoning in your hearts?
Luke 6:8
But He knew what they were thinking. Then He said to the man with the deformed hand, "Get up, step forward in front of everyone." So, he got up and stepped forward.
Luke 7:39
Now when the Pharisee who had invited Jesus saw this, he said to himself, "If this man were a prophet, he would have known who touched him and what kind of a woman she was --- a sinner."
John 2:24
But Jesus would not trust Himself to them [i.e., to the care of these Jewish leaders] because He knew all men,
John 6:64
But there are some of you who do not believe [in me]." For Jesus knew from the beginning which ones would not believe [in Him] and which one would turn Him over [i.e., to the Jewish authorities].
John 21:17
Then Jesus asked him a third time, "Simon, son of John, do you [truly] love me?" Peter was sad because Jesus had asked him a third time, "Do you [even] love me?" So, he said to Jesus, "Lord, you know all things. You [surely] know that I love you." Jesus replied to him, "[Then] feed my sheep.
Hebrews 4:13
And no created being is hidden from God's sight, but everything is laid bare and is openly visible to the eyes of God, to whom we must give account.
Revelation 2:23
And I will strike her children dead [or, "kill her children by some terrible calamity" See Ex. 5:3 LXX]. Then all the churches will know that I am the One who searches the inmost being of people [Note: The Greek says, "searches the kidneys and hearts." In that day these internal organs stood for the inner thoughts, emotions, etc.]. And I will repay each one of you people according to what you have done.

Why

Mark 7:21
For from within, out of people's hearts, proceed evil thoughts, sexual immorality, stealing, murder, extramarital affairs,
Luke 24:38
Then Jesus said to them, "Why are you [so] upset? And why are you having doubts [about me] in your minds?
Acts 5:3
But Peter said to Ananias, "Why has Satan filled your heart [causing you] to deceive the Holy Spirit by keeping back part of the selling price of the land [while representing it as the full price]?
Acts 8:22
So, repent [i.e., change your heart and life] of such a terrible thing and pray for the Lord to forgive you for even thinking of such a thing. Perhaps He will [if you are really sincere].

General references

John 20:23
Whosever sins you forgive, they will be forgiven [by God]. And whosever sins you do not forgive, they will not be forgiven [by God]." [Note: Actual forgiveness would result only when people responded, by faith, to the Gospel message. See Acts 2:37-38].