This quote comes from the book of Leviticus in the Bible and it refers to the ancient Jewish practice of animal sacrifice. In this context, the quote means that the life of a creature is contained in its blood, and that blood is a necessary part of the sacrificial process. According to Jewish tradition, animal sacrifice was a way to atone for sins and gain forgiveness from God. By offering the blood of a sacrificial animal on the altar, a person could make amends for their wrongdoing and be reconciled with God. Essentially, the quote is saying that blood was seen as a powerful symbol of life and that its use in sacrifices was a way to seek forgiveness and atonement