That is the plan of salvation. Salvation actually came to humanity in the person of Christ.
So Abraham was not saved? He believed in a Savior and his faith was credited to him as righteousness. Caleb’s and Joshua’s making it to the promised land while the others over 20, their bodies fell in the wilderness. A picture of the remnant that believed. Caleb and Joshua are in glory. The priests at the tabernacle preached a sufficient sacrifice every time they sacrificed an animal. God told Elijah that He preserved 7,000 that would did not bow a knee to Baal. The Old Testament saints were saved by their faith in the Promised Seed. God’s progressive revelation ensured that.