Today's first reading, Genesis 18:16-33, in which Abraham haggles with God for the sparing of Sodom, is one of my favorites in the daily Mass lectionary. I find it very encouraging and inspiring. I'll explain.
Even though we know that things didn't really work out for Sodom, it doesn't change the fact that God was willing to spare the whole city for the sake of ten innocent people, having been haggled down from fifty. I find this encouraging because it suggests that even though I'm a lukewarm religious and barely repentant for my sins, I could still be saved for the sake of the saints around in my in my friary, neighborhood, and world.
This means that it is in my best interest to help other people become saints, especially if it's not going so well for me. After all, it is the highest charity to assist others in coming to holiness, and this is what religious communities are meant to be at the most basic level: mutual associations for the sake of common and individual holiness.
God's oaths on the sparing of Sodom reveal that such charity, the giving of self for the sake of the holiness of others, is not just altruism. It is in my self-interest to give myself away for the sake of others arriving at holiness, because it may be because of their sanctity that a sinner and tepid religious like me could also come to salvation.