The effect of Peter's command to the lame man in Acts 3 was instant. He had no idea that he was about to walk. He wasn't asking or believing for healing, only a few coins. God healed him anyway because Peter believed. Peter told him to get up and walk, then pulled him to his feet without waiting for assent or protest. The man was instantly and totally healed. He didn't even have to learn to walk. No faith, repentance, alms, or prayer were required of him.

Miracles of healing aren't done by the power of men, but by the power of God acting through men with faith. Sometimes it's the faith of the one doing the healing, sometimes of the one being healed, and sometimes it's just because that's what God wants.