Verses with the word confirming in the New Testament (3 verses):

Mark 16:20
And they went forth, and preached every where, the Lord working with them, and confirming the word with signs following. Amen.

Acts 14:22
Confirming the souls of the disciples, and exhorting them to continue in the faith, and that we must through much tribulation enter into the kingdom of God.

Acts 15:41
And he went through Syria and Cilicia, confirming the churches.