Selfishness causes all sin. Integrity brings all happiness.
These two ideas are diametrically opposed to each other. One insinuates doing whatever it takes to get what you want, despite the consequences; the other is about doing the right thing all the time, even when nobody will know what your actions are. Adultery, thievery, lust, violence, lying, vanity, and every other bad, awful action that you can think of holds roots in the desire to make one's own status better or to satiate personal desires. Honesty, love, charity, faith, kindness, gentleness, diligence, generosity, and bravery, on the other hand, come from forgetting yourself in the desire to help and care for other people, no matter the time or the place. These choices have eternal consequences and every one must choose one or the other. As for me and my house? We will serve the Lord.