John 3:33

Whoever does receive it has set his seal that God is true.

John 6:27

"Labor not for food which perishes, but for the food that endures eternal life??hat which the Son of man will give you; for on the Father??od??as set his seal."

Romans 3:3-4

Supposing some of them have proved faithless?

Romans 4:18-21

For Abraham, hoping against hope, had faith to the end that he might become a father of many nations, according to that which had been spoken, So numberless shall your descendants be.

2 Corinthians 1:18

As God is faithful, my message to you is not now "Yes," now "No."

2 Corinthians 1:22

He has also set his seal upon me, and given me the pledge of his Spirit in my heart.

Ephesians 1:13

And in him, because you listened to the proclamation of the truth, the evangel of your salvation, and trusted it, you Gentiles too were sealed with the promised Holy Spirit,

Titus 1:1-2

To Titus, my true son in a common faith, from Paul, a slave of God, and an apostle of Jesus Christ, according to the faith of God's elect, and to the knowledge of the truth which goes with piety;

Hebrews 6:17

On which principle God, wishing to show more convincingly to the heirs of the promise the immutability of his purpose, mediated with an oath;

1 John 5:9-10

If we accept men's testimony, the testimony of God is greater; for this is the testimony of God, that he has borne testimony concerning his Son.

Revelation 7:3-8

saying, "Do no harm to the earth, or the sea, or the trees, Until we have sealed the slaves 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
Supposing some of them have proved faithless?
Romans 4:18
For Abraham, hoping against hope, had faith to the end that he might become a father of many nations, according to that which had been spoken, So numberless shall your descendants be.
2 Corinthians 1:18
As God is faithful, my message to you is not now "Yes," now "No."
Titus 1:1
To Titus, my true son in a common faith, from Paul, a slave of God, and an apostle of Jesus Christ, according to the faith of God's elect, and to the knowledge of the truth which goes with piety;
Hebrews 6:17
On which principle God, wishing to show more convincingly to the heirs of the promise the immutability of his purpose, mediated with an oath;
1 John 5:9
If we accept men's testimony, the testimony of God is greater; for this is the testimony of God, that he has borne testimony concerning his Son.