The pouring out of animal blood in the Old Testament was a sign of contrition and a rendering of the life of the sinner who offered the sacrifice back to God. That means living for God. If your life has been given to God, your life is to be used as God sees fit. It’s not a token offering – “God, I offer you my life” – and then go about your business like nothing has changed. I can’t say I am giving you my car and not hand over the keys and let you use it as you see fit. The blood of animals itself had no power, of course, to wash away sin. But it was the contrition of the one offering the sacrifice which was pleasing to God. Contrition means conversion. One who does no agree to end his sinful ways is clearly not sorry for his sinful ways. Sorrow means amending our ways.