The Wisdom of Israel, by Edwin Collins, , at sacred-texts.com
He who does an act of kindness to those who really need it, will have a greater reward than that of Abraham, who showed hospitality to angels. Abraham stood under a tree and waited on the three strangers while they ate and drank. And what reward had his descendants? The manna came down to them, and the springs of water rose up for them; quails came around them for their food, and the cloud of the Divine Glory stood to watch over them. But Abraham's guests were angels, who needed nothing: how much greater, then, will be the reward of those whose kindness is done to the poor, who need all things?
"Remember," says Rabbi Abin, "when a poor man stands at your door, The Holy One stands at his right hand."