This is a terrific question and an important one. Thanks for asking!! First of all, you are correct, the idea of God's permissive will cannot be understood in a way that either implicitly or explicitly suggests that God is necessarily in agreement with the thing being done simply because God allowed or permitted it to happen. The key idea here is that we cannot speak of the permissive will of God if by that we mean to say God desired or agreed with this particular outcome. If God desired or agreed with this particular event, then we simply call it the will of God. You might be aware that I have quoted Dietrich Bonhoeffer several times on this blog regarding events in our lives and the will of God. He says, [[Not everything that happens is the will of God, but inevitably, nothing that happens does so outside the will of God.]]
Ordinarily, I hear Bonhoeffer saying that God does not will our suffering, nor does God will evil, and at the same time, he will eventually bring good out of even these realities. I think this is a way of speaking about the permissive will of God relative to God's sovereign will. The basic idea is that God's plan and sovereignty are greater than even the worst things we choose to do to ourselves, to others, or to God's creation. God is greater than all sin and evil. Paul affirmed this when he said [[Where sin abounded, grace abounded all the more!]] God made us capable of choosing, which means he also created a world where sin is possible and can even come to dominate in various ways. Neither this fraught world nor the sin that dominates it is the will of God. And yet, God does not stop it; God permits it. But this permission does not mean God approves of sin or evil.I too have heard people speak of God's permissive will as though it indicates God's approval. Usually, it is meant to indicate God approves of something they have done because God didn't prevent it! For instance, in the name of "discernment," they will speak of something they are considering doing and feel unsure about. If God doesn't give them an out-and-out "sign" to not do the thing, they consider first that he is permitting it -- which God is!! They then argue it is okay and must have been God's will because God permitted it!! At this point, they refer to God's permissive will!! It's as though the phrase "God's permissive will" is a shorthand way of saying, "If God is permissive, then God must will whatever it is." There are many problems with this take on God's permissive will and the idea of "discernment" that propels it. Generally, it demonstrates an unformed and unsophisticated notion of discernment that depends on exterior signs from God. At the same time, it seems geared towards justifying an action one is uncomfortable about committing. In short, in adverting to God's permissive will in this way, one fails to listen to one's conscience (or to form it better) while calling upon God to give the person a sign! Meanwhile, one does all this while demeaning God in the process.And of course, we know all too well that God permits terrible, even horrific things that one could never argue must therefore have been God's will. One of the most common in Christianity is the crucifixion of Jesus. People argue that this must have been the will of God, though they won't go so far as saying those who carried this out (or egged them on!) were doing the will of God! They also won't suggest that Judas was doing the will of God in betraying Jesus, and rightly so (though their take on God's permissive will should cause them to say Judas was doing or expediting the will of God). But Jesus' passion and death are critical instances of God's permissive will, and the truth of Bonhoeffer's quote: [[Not everything that happens is the will of God, . . .]] God did NOT will Jesus' passion and death!! He willed Jesus to act with integrity, compassion, and courage in the face of evil. And Jesus did that! It is Jesus' resurrection and Ascension that prove the second part of Bonhoeffer's maxim, [[but inevitably, nothing that happens does so outside the will of God.]] While human beings may do their worst, and while God does not prevent this, these are NOT the will of God. At the same time, God's plan and sovereignty are both larger than we can imagine and ultimately will bring justice, that is, ultimately God will set all things to rights.You are correct that speaking as though God's permitting something means he agrees with it, makes God responsible for the evil that humankind does. God gives us the capacity to choose, as well as to learn and grow morally as well as intellectually, physically, emotionally, and spiritually. We have to trust in God's sovereignty if we are not to become completely discouraged with ourselves and the whole of humankind. This does not mean God is in total control, he is not. But it does mean that ultimately, the evil that we do is finite, and God's plan for a new heaven and new earth will encompass and transcend even the worst we do to ourselves and one another!