John 3:33

He that hath received his witness hath set his seal to this , that God is true.

John 6:27

Work not for the food which perisheth, but for the food which abideth unto eternal life, which the Son of man shall give unto you: for him the Father, even God, hath sealed.

Romans 3:3-4

For what if some were without faith? shall their want of faith make of none effect the faithfulness of God?

Romans 4:18-21

Who in hope believed against hope, to the end that he might become a father of many nations, according to that which had been spoken, So shall thy seed be.

2 Corinthians 1:18

But as God is faithful, our word toward you is not yea and nay.

2 Corinthians 1:22

who also sealed us, and gave us the earnest of the Spirit in our hearts.

Ephesians 1:13

in whom ye also, having heard the word of the truth, the gospel of your salvation,-- in whom, having also 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, according to the faith of God's elect, and the knowledge of the truth which is according to godliness,

Hebrews 6:17

Wherein God, being minded to show more abundantly unto the heirs of the promise the immutability of his counsel, interposed with an oath;

1 John 5:9-10

If we receive the witness of men, the witness of God is greater: for the witness of God is this, that he hath borne witness concerning his Son.

Revelation 7:3-8

saying, Hurt not the earth, neither the sea, nor the trees, till we shall 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 were without faith? shall their want of faith make of none effect the faithfulness of God?
Romans 4:18
Who in hope believed against hope, to the end that he might become a father of many nations, according to that which had been spoken, So shall thy seed be.
2 Corinthians 1:18
But as God is faithful, our word toward you is not yea and nay.
Titus 1:1
Paul, a servant of God, and an apostle of Jesus Christ, according to the faith of God's elect, and the knowledge of the truth which is according to godliness,
Hebrews 6:17
Wherein God, being minded to show more abundantly unto the heirs of the promise the immutability of his counsel, interposed with an oath;
1 John 5:9
If we receive the witness of men, the witness of God is greater: for the witness of God is this, that he hath borne witness concerning his Son.

American Standard Version Public Domain