knowing that you were redeemed, not with corruptible things, with silver or gold, from the useless way of life handed down from your fathers,

 (iii) The Christian is chosen for obedience and for sprinkling by the blood of Jesus Christ. In the Old Testament there are three occasions when sprinkling with blood is mentioned. It may well be that all three were present in Peter's mind and that all three have something to contribute to the thought behind these words. 