1 Corinthians 2:14

But a natural man does not accept the things of the Spirit of God, for they are foolishness to him; and he cannot understand them, because they are spiritually appraised.

1 Corinthians 1:18

For the word of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God.

Jude 1:19

These are the ones who cause divisions, worldly-minded, devoid of the Spirit.

Matthew 13:11-17

Jesus answered them, To you it has been granted to know the mysteries of the kingdom of heaven, but to them it has not been granted.

1 Corinthians 15:44

it is sown a natural body, it is raised a spiritual body. If there is a natural body, there is also a spiritual body.

Matthew 16:23

But He turned and said to Peter, “Get behind Me, Satan! You are a stumbling block to Me; for you are not setting your mind on God’s interests, but man’s.”

John 3:3-6

Jesus answered and said to him, “Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God.”

John 5:44

How can you believe, when you receive glory from one another and you do not seek the glory that is from the one and only God?

John 8:51-52

Truly, truly, I say to you, if anyone keeps My word he will never see death.”

1 Corinthians 15:46

However, the spiritual is not first, but the natural; then the spiritual.

James 3:15

This wisdom is not that which comes down from above, but is earthly, natural, demonic.

Proverbs 14:6

A scoffer seeks wisdom and finds none,
But knowledge is easy to one who has understanding.

John 6:44-45

No one can come to Me unless the Father who sent Me draws him; and I will raise him up on the last day.

John 8:43

Why do you not understand what I am saying? It is because you cannot hear My word.

John 10:20

Many of them were saying, “He has a demon and is insane. Why do you listen to Him?”

John 10:26-27

But you do not believe because you are not of My sheep.

John 12:37

But though He had performed so many signs before them, yet they were not believing in Him.

John 14:26

But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all that I said to you.

John 15:26

“When the Helper comes, whom I will send to you from the Father, that is the Spirit of truth who proceeds from the Father, He will testify about Me,

John 16:8-15

And He, when He comes, will convict the world concerning sin and righteousness and judgment;

Acts 16:14

A woman named Lydia, from the city of Thyatira, a seller of purple fabrics, a worshiper of God, was listening; and the Lord opened her heart to respond to the things spoken by Paul.

Acts 17:18

And also some of the Epicurean and Stoic philosophers were conversing with him. Some were saying, “What would this idle babbler wish to say?” Others, “He seems to be a proclaimer of strange deities,”—because he was preaching Jesus and the resurrection.

Acts 17:32

Now when they heard of the resurrection of the dead, some began to sneer, but others said, “We shall hear you again concerning this.”

Acts 18:15

but if there are questions about words and names and your own law, look after it yourselves; I am unwilling to be a judge of these matters.”

Acts 25:19

but they simply had some points of disagreement with him about their own religion and about a dead man, Jesus, whom Paul asserted to be alive.

Acts 26:24-25

While Paul was saying this in his defense, Festus *said in a loud voice, “Paul, you are out of your mind! Your great learning is driving you mad.”

Romans 8:5-8

For those who are according to the flesh set their minds on the things of the flesh, but those who are according to the Spirit, the things of the Spirit.

1 Corinthians 1:23

but we preach Christ crucified, to Jews a stumbling block and to Gentiles foolishness,

1 Corinthians 2:12

Now we have received, not the spirit of the world, but the Spirit who is from God, so that we may know the things freely given to us by God,

2 Corinthians 4:4-6

in whose case the god of this world has blinded the minds of the unbelieving so that they might not see the light of the gospel of the glory of Christ, who is the image of God.

1 John 2:20

But you have an anointing from the Holy One, and you all know.

1 John 2:27

As for you, the anointing which you received from Him abides in you, and you have no need for anyone to teach you; but as His anointing teaches you about all things, and is true and is not a lie, and just as it has taught you, you abide in Him.

1 John 5:20

And we know that the Son of God has come, and has given us understanding so that we may know Him who is true; and we are in Him who is true, in His Son Jesus Christ. This is the true God and eternal life.

Treasury of Scripture Knowledge

Summary

But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned.

Bible References

Receiveth

Matthew 13:11
Jesus answered them, To you it has been granted to know the mysteries of the kingdom of heaven, but to them it has not been granted.
Matthew 16:23
But He turned and said to Peter, “Get behind Me, Satan! You are a stumbling block to Me; for you are not setting your mind on God’s interests, but man’s.”
John 3:3
Jesus answered and said to him, “Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God.”
John 8:43
Why do you not understand what I am saying? It is because you cannot hear My word.
John 10:26
But you do not believe because you are not of My sheep.
John 12:37
But though He had performed so many signs before them, yet they were not believing in Him.
Romans 8:5
For those who are according to the flesh set their minds on the things of the flesh, but those who are according to the Spirit, the things of the Spirit.

The things

1 Corinthians 2:12
Now we have received, not the spirit of the world, but the Spirit who is from God, so that we may know the things freely given to us by God,
John 14:26
But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all that I said to you.
John 15:26
“When the Helper comes, whom I will send to you from the Father, that is the Spirit of truth who proceeds from the Father, He will testify about Me,
John 16:8
And He, when He comes, will convict the world concerning sin and righteousness and judgment;

They

1 Corinthians 1:18
For the word of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God.
John 8:51
Truly, truly, I say to you, if anyone keeps My word he will never see death.”
John 10:20
Many of them were saying, “He has a demon and is insane. Why do you listen to Him?”
Acts 17:18
And also some of the Epicurean and Stoic philosophers were conversing with him. Some were saying, “What would this idle babbler wish to say?” Others, “He seems to be a proclaimer of strange deities,”—because he was preaching Jesus and the resurrection.
Acts 18:15
but if there are questions about words and names and your own law, look after it yourselves; I am unwilling to be a judge of these matters.”
Acts 25:19
but they simply had some points of disagreement with him about their own religion and about a dead man, Jesus, whom Paul asserted to be alive.
Acts 26:24
While Paul was saying this in his defense, Festus *said in a loud voice, “Paul, you are out of your mind! Your great learning is driving you mad.”

General references

Proverbs 8:9
“They are all straightforward to him who understands,
And right to those who find knowledge.
Proverbs 28:5
Evil men do not understand justice,
But those who seek the Lord understand all things.
Luke 7:23
Blessed is he who does not take offense at Me.”
John 1:5
The Light shines in the darkness, and the darkness did not comprehend it.