'Confirms' in the Bible

The Spirit himself confirms to our spirit that we are children of God,

I am telling the truth because I belong to the Messiah I am not lying, and my conscience confirms it by means of the Holy Spirit.

For with the heart a person believes [in Christ as Savior] resulting in his justification [that is, being made righteous—being freed of the guilt of sin and made acceptable to God]; and with the mouth he acknowledges and confesses [his faith openly], resulting in and confirming [his] salvation.

Now it is God who strengthens us, with you, in Christ and has anointed us.

saying, "This is the blood which confirms the Covenant that God has made binding upon you."

Children, it is the last hour [the end of this age]; and just as you heard that the antichrist is coming [the one who will oppose Christ and attempt to replace Him], even now many antichrists (false teachers) have appeared, which confirms our belief that it is the last hour.