What his particular impotency was the Scripture doth not tell us. Some have (not improbably) judged it the palsy, which deprives the person of motion, by the stoppage of the animal spirits, so that without help he cannot move from one place to another, which it is manifest this poor man could not; for he complains for want of help, that he could not get into the pool.
Related Commentaries of John 5:7
John 5:7
7 The impotent man answered him, Sir, I have no man, when the water is troubled, to put me into the pool: but while I am coming, another steppeth down before me.