How much does the Church say that God directly interferes with our lives? (Or, indeed, the devil?)
If you pray for something to happen, and it happens, does that make it God’s ‘fault’ (in the positive sense)? If you are fairly sure that the thing which you prayed for would have happened anyway, should you still ascribe the thing’s happening to God?
If you sin, does God punish you on Earth, or cause things to happen which will reform you?
I would answer yes to pretty much all of the above. Put it this way: according to the idea of God’s causal omnipresence, our entire existence from its beginning is indirectly due to God’s “interference,” if you want to put it that way. Our ongoing lives are due to God’s ongoing causal relationship to us.
So why pray about things, if our lives are in God’s hands anyway? Well, if God sees all of our lives in one eternal instant, He also sees all our prayers. In his causation of our lives, couldn’t He take into consideration the prayers we haven’t even prayed yet? And if we in fact do not pray, God already sees that as well, and it is as well taken into consideration.
Example: my wife and I once needed a certain amount of money, and we prayed for it. The next day, the exact amount we prayed for arrived in the mail (it was an unexpected state tax adjustment we didn’t even know about). Now think about it: the check had to have been mailed before we prayed, in order to get to us the next day. In one sense, I could say there couldn’t be a causal relationship there, from my linear-time perspective. However, there COULD be a causal relationship there, given that God saw our prayers and saw the answer simultaneously. The arrangement of prayer / answer is just given to us, I think, to strengthen our faith.
This is all sort of speculation on my part; however, C.S. Lewis thought the same thing. (Appeal to authority, I know.)
As for sin, that’s also complicated. But some sins tend to carry their own punishment with them, given natural-law factors. Gluttony, for example, and others I’m too politically correct to mention.