How do you resist the devil? In his commentary, John Calvin addressed that very question, “Not every kind of faith that will suffice, when we have to enter into a serious conflict with Satan, but that vigorous efforts are indispensably necessary.” This passage is not the first time Mark records the casting out of an evil spirit by Jesus’ disciples. Already they had successfully cast out many evil spirits by the authority which Jesus gave them (6:13–27). Nor was it the first time they saw Jesus encounter an evil spirit. Their first lesson in casting out demons occurred when they were still new disciples. They were with Jesus at a synagogue when He cast out an unclean spirit (1:23–26). And then, in their sight, He had ordered evil spirits out of the Gerasenes demoniac (5:13) and the Syrophoenician woman’s daughter (7:29). Certainly by now the disciples were knowledgeable and experienced at casting out evil spirits. So why were they not able to cast out this particular one? Jesus pressed into the situation, recognizing the length of time the boy had been tormented by the spirit and the lack of faith present in both the “unbelieving generation” (v. 19) and the father. He advises the use of prayer— prayer, apparently, of great faith (v. 29). Somewhere in following Jesus, even as they had successfully cast out other evil spirits, the disciples had missed the lessons on deep and fertile praying. In our efforts to follow Christ well and make disciples, it is important to emphasize and re-emphasize prayer as the means to accomplishing work in His power. Facing the evil one in both seen and unseen realms requires prayer accompanied by great faith. Christ has the power for us to successfully overcome all evil.