Vana Parva 200.105

He who gives away a horse at a Tirtha where the current of the water runs in an opposite direction obtains merits that are inexhaustible. A guest who comes for food is Indra himself. If he is entertained with food, Indra confers on the feeder merits that are inexhaustible. As men cross rivers and seas by boats, so is he saved from all his sins (by giving board to guests).