[If so,] I will punish him most severely or will kill him unless he bring me a convincing excuse!"

"I will certainly punish him with a severe penalty, or execute him, unless he bring me a clear reason (for absence)."

I verily will punish him with hard punishment or I verily will slay him, or he verily shall bring me a plain excuse.

I will certainly punish him with a severe punishment, or kill him, or he shall bring me a clear excuse.

I will surely punish him with a severe punishment or slaughter him unless he brings me clear authorization."