Blood

Blood is linked to the life force of humans and animals in the Old Testament. This is why it is forbidden for Israelites to consume blood, or meat that still has blood in it. At the same time, blood, as an embodiment of life, plays an important part in (purification) rituals.

The Consumption of Blood

Because blood signifies life, it belongs to God. Consuming blood is therefore restricted in the Bible. Neither heathens nor Israelites are allowed to consume blood from living animals (Genesis 9:4). “Bleeding” living animals in order to drink their blood was in fact a custom that existed among certain cultures. However, the Bible forbids this.
In addition to this, Israelites may not consume blood from slaughtered animals, or even the meat of a dead animal if it still contains blood (Leviticus 7:26-27; Deuteronomy 12:23-24).

Use of Blood in Rituals

Blood as a vessel for life force is used in various rituals in the Old Testament:

Blood can serve as a means of reconciliation between God and man. The blood and fat of a sacrificial animal gives life to sinners (Leviticus 17:11).
Blood is used in rituals to protect the living from the powers of death, such as the blood that was applied to the doorposts by the Israelites in Exodus 12:7.
In purification rituals blood also plays an important part. Blood cleanses the altar (Ezekiel 43:20) and the Temple (Ezekiel 45:18-20), and is used to cleanse people with a skin disease (Leviticus 14:1-7). (See impurity in people.)
Blood has a function in initiation ceremonies: new priests are sprinkled with blood from the offerings (Exodus 29:9-21; Leviticus 8:24). Here the blood symbolises the new life that they are given.

Blood as a Source of Impurity

In certain circumstances, blood is in fact a source of impurity in the Old Testament:

Innocent blood: shedding the blood of innocent people causes bloodguilt. This makes the land unclean (Numbers 35:33-34; Deuteronomy 19:10-13; Jeremiah 7:6).
Menstrual blood or post-natal flow: in the Old Testament, menstrual blood serves as the archetypical impurity (Leviticus 20:18; Ezekiel 36:17). Similarly, the blood flow after childbirth makes a woman temporarily unclean (Leviticus 12:1-8). (See impurity in people.)