I dont think I understand sin and divine providence. Is it that God does not CAUSE people to sin but rather works concurrently with it and orders it for his purposes. Or is there more to it than that?
There is more to it than that but it needs a book - or at least some trawling the net.
From John Calvin comes the idea that God may not "cause" sin but may "ordain" it. "Calvinist" may be shorthand for the concept that "all things, come not by chance, but by God's fatherly hand” (the Heidelberg Catechism). "Arminianism" (from Jacobus Arminius) rather sees sin as the consequence of God's giving us free will (God causes us to be able to sin).
These 16th century arguments are still going. Here's a fairly recent summary of the opposing views: http://thinktheology.co.uk/blog/article/does-god-ordain-all-sinful-human-choices
If you google god "author of sin" patristic
you'll link to a recent study by Christopher Eppling (A Study of the Patristic Doctrine of Free Will) on how the early church fathers addressed this - probably taking you straight to a comment by Clement of Alexandria (2nd/3rd century) that the blame lies with the one who chooses, while "God is without blame".