What does blood convenant mean in the New Testament?

A covenant is also called a testament. The covenant that God made with Abraham in Genesis is now considered the old covenant and it was put into force with blood.

Among the Old Testament sacrifices were animal sacrifices in which an animal was slain (blood Sacrifice). When God made the covenant with Abraham, God had Abraham gather up a heifer, a goat, a ram, a turtledove, a pigeon. The animals were then all cut in two and that night a deep sleep fell upon Abraham and the presence of God walked between the pieces. A blood covenant had occurred.

In the New Testament Jesus Christ came to save sinners and to usher in the New Covenant. Jesus was the Testator of the New Covenant. We are told that as long as the testator is still alive the covenant (testament) is not in affect. Animal sacrifices could never take away the sin of the world, only the blood of Jesus could do that. When Jesus died on the cross (Shed his Blood) the new covenant (Testament) became active. The death of Jesus the Christ was a blood Covenant. Praise God that on the third day Jesus resurrected from the dead and is now in heaven making intercession for those who love Him. Soon he will return to take His own to heaven.

Additional Comment:

Hebrews 9:18-23New King James Version (NKJV)

18 Therefore not even the first covenant was dedicated without blood. 19 For when Moses had spoken every precept to all the people according to the law, he took the blood of calves and goats, with water, scarlet wool, and hyssop, and sprinkled both the book itself and all the people, 20saying, "This is the blood of the covenant which God has commanded you."[a]21 Then likewise he sprinkled with blood both the tabernacle and all the vessels of the ministry. 22 And according to the law almost all things are purified with blood, and without shedding of blood there is no remission.

Greatness of Christ's Sacrifice23 Therefore it was necessary that the copies of the things in the heavens should be purified with these, but the heavenly things themselves with better sacrifices than these.

Footnotes:

1. Hebrews 9:20 Exodus 24:8