Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin unto death, or of obedience unto righteousness. Rom. 6:16.
"Every soul that refuses to give himself to God is under the control of another power. He is not his own. He may talk of freedom, but he is in the most abject slavery....While he flatters himself that he is following the dictates of his own judgment, he obeys the will of the prince of darkness."--The Desire of Ages, p. 466. "Unless we do yield ourselves to the control of Christ, we shall be dominated by the wicked one. We must inevitably be under the control of one or the other of the two great powers that are contending for the supremacy of the world."--Ibid., p. 324.
Everyone in this world, everyone in the church, is under the control either of God or of Satan. As we choose to enter into the faith relationship with God, this enables Him to be in control of our direction, and our direction will be upward, in spite of the occasional misdeed. If we do not choose to have a relationship with God (and there are too many church members who have not), then our direction is controlled by Satan, and it will be downward, in spite of the occasional good deed.
God's ultimate goal for us is that not only will He be in control of our direction but that we will continue this relationship until He is able to lead us to be under His absolute control all of the time. He will hold over us absolute sway--by our own choice. And we will be possessed by the Holy spirit. Don't tell me that that kind of person would be unable to obey!
The devil's purpose is that we will stay apart from a relationship with Jesus so that he will have control of our direction, until he reaches his goal for us. His ultimate goal is to have us under his absolute sway, and have us possessed by him. And, please, devil possession can be manifested in more ways than just frothing at the mouth and rolling in the dirt. The Pharisees in the days of Christ were possessed by the same evil spirit as the demoniac in the Temple.
When realize our condition as sinners, and surrender ourselves to the control of God, He brings us to the point of obedience--obedience by faith in Him alone. To be controlled by God is the only route to genuine obedience.