Matthew 14:7

14:7 so much that he promised with an oath to give her whatever she asked.

Matthew 26:72

26:72 He denied it again with an oath, “I do not know the man!”

tn The Greek text reads here ὁμολογέω (Jomologew); though normally translated “acknowledge, confess,” BDAG (708 s.v. 1) lists “assure, promise with an oath” for certain contexts such as here.