Does Satan or the Old Adam constantly push believers to follow the old nature?
The Old Adam is the constant internal force pushing believers toward the old nature. Though Satan also attacks, the Old Adam more regularly confronts them, pops thoughts into their minds, and catches them in weakness. Opposite this, the new nature is energized by the Holy Spirit.
Les teaches that Paul's statement “I am crucified” refers to Saul of Tarsus dying in the Old Adam on the Damascus road when he recognized the Ascended Jesus as the Crucified One. At that moment he became a new man, a new creation. This is Paul's thrust: believers now have two forces working within them. God reckons Old Adam absolutely dead, but in experience he is still there. Les says he minds the attacks of Satan less than the attacks of his Old Adam. As believers go through life, most difficulty comes not from Satan as much as from Old Adam. Old Adam pops thoughts into the mind and catches us in moments of weakness. Les does not take away from Satan's power, but it is the Old Adam that constantly confronts believers to still go the direction of the Old Adamic nature. Opposite it is the new nature, energized by the Holy Spirit.