John 3:33

He that hath received his testimony, hath set his seal to this, that God is true:

John 6:27

Labour not so much for the meat that perisheth, but rather for that food which endureth unto life eternal, which the Son of man will give you: for Him hath God the Father sealed.

Romans 3:3-4

For what if some did not believe? shall their incredulity make the faithfulness of God of no effect?

Romans 4:18-21

who against hope believed, with hope, that he should be the father of many nations, according to that which was said unto him, "So shall thy seed be."

2 Corinthians 1:18

But the faithful God, He knows, that our word to you was not yes and no.

2 Corinthians 1:22

and given us the earnest of the Spirit in our hearts.

Ephesians 1:13

In whom ye also trusted, when ye heard the word of truth, the gospel of your salvation: in whom also when ye believed, ye were sealed with the holy Spirit of promise,

Titus 1:1-2

Paul a servant of God, and an apostle of Jesus Christ, for promoting the faith of God's chosen people, and the knowledge of the truth which is according to godliness:

Hebrews 6:17

Wherefore God being willing more abundantly to manifest unto the heirs of the promise the immutability of his counsel, confirmed it with an oath:

1 John 5:9-10

Now if we admit the testimony of men, sure the testimony of God is greater: and this is the testimony of God, which He hath testified concerning his Son.

Revelation 7:3-8

saying, Hurt not the earth, nor the sea, nor the trees, till we have sealed the servants of our God on their foreheads.

Treasury of Scripture Knowledge

Summary

He that hath received his testimony hath set to his seal that God is true.

Bible References

Hath set

Romans 3:3
For what if some did not believe? shall their incredulity make the faithfulness of God of no effect?
Romans 4:18
who against hope believed, with hope, that he should be the father of many nations, according to that which was said unto him, "So shall thy seed be."
2 Corinthians 1:18
But the faithful God, He knows, that our word to you was not yes and no.
Titus 1:1
Paul a servant of God, and an apostle of Jesus Christ, for promoting the faith of God's chosen people, and the knowledge of the truth which is according to godliness:
Hebrews 6:17
Wherefore God being willing more abundantly to manifest unto the heirs of the promise the immutability of his counsel, confirmed it with an oath:
1 John 5:9
Now if we admit the testimony of men, sure the testimony of God is greater: and this is the testimony of God, which He hath testified concerning his Son.