It polishes your soul, thus making you more likely to get into heaven, and thereby gain eternal bliss. Also, it pleases God (apparently, or so he says).
Ok, I should have said that the idea of actions being “good” and “evil” are abitary. Futhermore, the goals that a moral system is designed to achieve by promoting certain types of behaviour are in turn arbitary. Therefore, any form of constructed system of morality that does not rely on the absolute authority of a supernatural agency is, by definition, artificial and arbitary. This does not make it inferior to a supernatural-defined morality system, but I think it is important to recognise that without an absolute morality, the system is human-created and, therefore, arbitarilly chosen.
Hmm, yes and no. New Testament God* wants you to pray to him, not to help Him, but to help yourself. He has an agenda to promote (saving the deserving members of the human race- how He arrived at the definition of “deserving” is for another thread) and a key step in that plan is getting the mortals to realise his goodness and existence. Thus, prayer.
But if you believe in God (which is how I phrased my original comment** it does. It helps to redeem the world, starting with you (this could, I admit, be construed as selfish- just a little :D).
Something I addressed in that old woman parable. New Testament God wants good deeds, but they have to be backed up by prayer. Why? Because unless they are committed in pursuit of God’s purpose, good deeds are apparently worthless- more like doing good through accident than by knowing what the right thing is and then doing it.
*Important distinction. Old Testament God is presented as just a destrutive and unpleasent bully, with few redeeming features and an argument that always boils down to “me God!”. Here, he is unquestionably a “jealous God” who demands worship.