I love these words from Jonathan Edwards (in Charity And Its Fruits):
If you are selfish, and make yourself and your own private interests your idol, God will leave you to yourself, and let you promote your own interests as well as you can.
But if you do not selfishly seek your own, but do seek the things that are Jesus Christ’s, and the things of your fellow human beings, then God will make your interest and happiness his own charge, and he is infinitely more able to provide for and promote it than you are. The resources of the universe move at his bidding, and he can easily command them all to subserve your welfare.
So that, not to seek your own, in the selfish sense, is the best way of seeking your own in a better sense. It is the directest course you can take to secure your highest happiness.
I would say that this might be the second most important thing I have ever read.