https://www.mljtrust.org/sermons-online/acts-7-1-3/get-thee-out-of-thy-country/

God’s great plan of salvation is found in Jesus Christ. But as Dr. Martyn Lloyd-Jones explains through Stephen’s sermon on Acts 7, this plan of salvation was foreseen in the Old Testament and in the sacrificial system. One clear foretelling came when God commanded Abraham to sacrifice his only son Isaac upon an altar. While in the end God provides a ram for Abraham to sacrifice instead of his son, this looks forward to when God gives His only Son to die upon the cross for the sins of the world. God tells that the blood of bulls and goats will not atone for sins and Dr. Lloyd-Jones proclaims that it is only the perfect blood of Jesus Christ, true God and true man, that can take away sins and make sinners righteous. This is the whole message of the Old Testament: the need of salvation for all and the need for God to supply the means of this salvation. This is why the Old Testament is so central to Christianity; the Old Testament tells of the need of salvation and of the futility of human means. It is the overarching narrative of Scripture that tells of the fallenness of humanity and the great gospel of Christ that is the only salvation of the world.