Why did Abraham and the Old Testament saints have no concept of Christ's death, burial, resurrection, and atoning blood?

Abraham and the Old Testament saints lacked this concept because God did not expect them to die. While resurrection and Israel’s coming redemption were on Abraham’s mind, they could not associate redemption with a death, burial, resurrection, and the shedding of Christ’s atoning blood.

Les explains that Abraham did have the concept of resurrection and of Israel coming into a place of Redemption on his mind. However, Abraham and the Old Testament saints could not associate that redemption with a death, burial, and resurrection, nor with the shedding of the atoning blood of Christ. The reason given is that God did not expect them to die. The context later contrasts this with believers who come into a right relationship by faith, blessed with Abraham, the friend of God, because of what God accomplished in the work of the cross.

Why didn't Abraham and the Old Testament saints understand the death, burial, and resurrection of Christ and His atoning blood?

Abraham and the Old Testament saints understood resurrection and Israel's redemption, but could not associate these with Christ's death, burial, resurrection, and atoning blood. The context says they had no concept of that because God did not expect them to die, so that truth was not part of their understanding.