Atonement. The third ritual effect associated with blood is the making of atonement (e.g., Lev 8:15; 16:16–19). Atonement is a complex theological topic and the exact process and nature of atonement is debated. However, it can be generally understood as a state of restoration or reconciliation. In the Old Testament, atonement is associated with the Hebrew root כפר (kpr), often defined as “cover” (see Rodrigues, “Atonement”). Milgrom points out that while “atone” is a common translation for כפר (kpr), the actual usage of the word reveals a much more complicated range of possible meanings in context, including “wipe,” “remove,” “purify,” “decontaminate,” “cover,” “rub,” and “ransom”; Milgrom prefers to use “purge” in most contexts (Milgrom, Leviticus 1–16, 1079–82).

Blood is a key ingredient for bringing about atonement in the biblical system. Most cases where a priest makes atonement for someone or something involve an animal sacrifice (e.g., Lev 1:4; 4:20; 5:6), though there were exceptions where a monetary offering was required for atonement (e.g., Exod 30:11–16). The practice of animal sacrifice for atonement is commonly interpreted as a case of substitution—where the animal’s blood is offered in place of the sinner’s to expiate (or remove) the person’s guilt (Rooker, Leviticus, 53). According to Hebrews 9:22, blood is an essential ingredient for atonement (for how ἄφεσις, aphesis; relates to atonement, see Koester, Hebrews, 420–21).