'Confirming' in the Bible

Then Queen Esther, the daughter of Abihail, with Mordecai the Jew, wrote with full power and authority to confirm this second letter about Purim.

And they went out and preached everywhere, while the Lord was working with them and confirming the word by the signs that followed.]

For I tell you that Christ has become a servant and a minister to the circumcision (Jews) on behalf of God’s truth, to confirm and verify the promises made to the fathers,

If I am not [considered] an apostle to others, at least I am one to you; for you are the seal and the certificate and the living evidence of my apostleship in the Lord [confirming and authenticating it].