'Confirmation' in the Bible

It is right for me to feel this way about you, because [you have me in your heart as] I have you in my heart, since both in my imprisonment and in the defense and confirmation of the good news [regarding salvation], all of you share in [His matchless] grace with me.

Indeed men swear [an oath] by one greater than themselves, and with them [in all disputes] the oath serves as confirmation [of what has been said] and is an end of the dispute.

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].