Adam Clarke on Zechariah 13:5

But he shall say, I am no prophet - This must be the case of a false prophet or diviner, who had been obliged to give up his infamous practice, and become even a laborer in the land. But having been known to be such, he is questioned by the people to see if he still were addicted in heart to the same practices. He declares he is no prophet, neither true nor false; that he is now a husbandman, and was brought up a herdsman.