'Confirmation' in the Bible

For all the promises of God, whatever their number, have their confirmation in Him; and for this reason through Him also our "Amen" acknowledges their truth and promotes the glory of God through our faith.

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.

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

And the Holy Spirit also adds His testimony to us [in confirmation of this]; for after having said,

Now faith is the assurance (title deed, confirmation) of things hoped for (divinely guaranteed), and the evidence of things not seen [the conviction of their reality—faith comprehends as fact what cannot be experienced by the physical senses].