Even Satan cannot do anything, unless the Lord lets him, see Job 1.
Saying that Satan is not doing God's will may have two meanings, in the same way
as the debate over man's free will caused divisions between churches. Firstly:
Man (Satan) is responsible for all he does; secondly nothing happens without the
will of our heavenly Father, see what Jesus says about the sparrows in the
temple. We are in big trouble, if we start to deny that God is almighty, and
say that what satan does is outside God's will. God uses pagan nations
(satan's) to punish Israel in the OT, even when He then punishes the heathen
nations for what they did to Israel. Satan is a creature, who is fighting God.
God uses even Satan, to show His power.
God is Almighty, man is "free" to sin, therefor responsible. And nothing
can happen unless God wills it. If our brains cannot comprehend it, we say it
is a contradiction. But who are we? May we judge how God works? We just
listen to His Word. Please, let us not reason a so-called contradiction away.
Jan de Koning