Greater Good

Oracle Text

Sacrifice a creature: Draw cards equal to the sacrificed creature's power, then discard three cards.

Card Rulings

8/1/2005 You must discard three cards regardless of how many cards you drew. If you have less than three cards in hand, you discard your hand.
8/1/2005 You draw cards equal to the creature’s power when you sacrificed it. This includes any bonuses from effects like Giant Growth.