Verses with the word confirmation in the New Testament (2 verses):

Philippians 1:7
Even as it is meet for me to think this of you all, because I have you in my heart; inasmuch as both in my bonds, and in the defence and confirmation of the gospel, ye all are partakers of my grace.

Hebrews 6:16
For men verily swear by the greater: and an oath for confirmation is to them an end of all strife.