Who is he that will plead with me? for now, if I hold my tongue, I shall give up the ghost.
If ... - rather, 'then would I hold my tongue, and give up the ghost;' i:e., if any one can contend with me, and prove me false, I have no more to say; 'I will be silent, and die.' Like our 'I would stake my life on it' (Umbreit).