Job’s story demolishes the notion that we can avoid Satan’s attacks if we’re sufficiently strong, or skilled enough, or trained in how to wage war against Satan. No one was more spiritually fit than Job. Yet God allowed Satan to ravage him anyway – and there was nothing Job could do about it. Job finally prevailed in the face of Satan’s merciless assault, not because he found some secret way to beat the devil, not because he rebuked him or ordered him to desist, but because God was in control all along. He knew how much Job could bear. And He would not permit Satan to cross that boundary (1 Cor. 10:13). When Satan reached that limit God stopped him and his attacks ended.
John MacArthur