John 3:33
They who did accept his statement attested the fact that God is true.
John 6:27
Work, not for the food that perishes, but for the food that lasts for Immortal Life, which the Son of Man will give you; for upon him the Father--God himself--has set the seal of his approval."
2 Corinthians 1:22
Also set his seal upon us, and gave us his Spirit in our hearts as a pledge of future blessings.
Ephesians 1:13
And you, too, by your union with him, after you had heard the Message of the Truth, the Good News of your Salvation--you believed in him and were sealed as his by receiving the holy Spirit, which he had promised.
Ephesians 4:30
And do not grieve God's Holy Spirit; for it was through that Spirit that God sealed you as his, against the Day of Redemption.
Revelation 7:2
And, in the east, I saw another angel, ascending, holding the seal of the Living God; and he cried in a loud voice to the four angels, to whom there had been given power to harm the earth and the sea--
Revelation 9:4
They were told not to harm the grass, or any plant, or any tree, but only those who have not 'the seal of God upon their foreheads.'