Jamieson, Fausset & Brown

But Herod, &c.--See on Mar 6:14, &c. (Also see on Mat 3:12.) and for all the evils which Herod had done--important fact here only mentioned, showing how thoroughgoing was the fidelity of the Baptist to his royal hearer, and how strong must have been the workings of conscience in that slave of passion when, notwithstanding such plainness, he "did many things and heard John gladly" (Mar 6:20, Mar 6:26).