'Confirm' in the Bible

Do we then nullify the Law by this faith [making the Law of no effect, overthrowing it]? Certainly not! On the contrary, we confirm and establish and uphold the Law [since it convicts us all of sin, pointing to the need for salvation].

so that He may strengthen and establish your hearts without blame in holiness in the sight of our God and Father at the coming of our Lord Jesus with all His saints (God’s people).

You too, be patient; strengthen your hearts [keep them energized and firmly committed to God], because the coming of the Lord is near.