John Calvin Commentary 1 Corinthians 15:11

"Whether then [it be] I or they, so we preach, and so ye believed." — 1 Corinthians 15:11 (ASV)

Whether I or they—Having compared himself with the other Apostles, he now associates himself with them, and them with him, in agreement as to their preaching. “I do not now speak of myself, but we have all taught so with one voice, and still continue to teach so.” For the verb κηρύσσομεν (we preach) is in the present tense — intimating a continued act, or perseverance in teaching. “If, then, it is otherwise, our apostleship is void: indeed — so you believed: your religion, therefore, is in vain.”