For I suppose I was not a whit behind the very chiefest apostles.

I consider myself in no way inferior to those “super-apostles.”

I am become a fool in glorying; ye have compelled me: for I ought to have been commended of you: for in nothing am I behind the very chiefest apostles, though I be nothing.

I have become a fool, but you drove me to it. In fact, you should have commended me, since I am in no way inferior to those “super-apostles,” even though I am nothing.