How was salvation achieved prior to the Resurrection of Christ and the spreading of Christianity?
Salvation has always been a gift of God’s grace, received by faith alone. While today believers look back to the death and resurrection of Christ as that which makes God’s gift of salvation possible, before the time of Christ believers looked forward to the coming of a Savior. This Savior, or Deliverer, would be of the seed of the woman (Gen. 3:15), the seed of Abraham (Gen. 12:1-3; Gen. 15:6), and the seed of David (2 Sam. 7:12-17; see also Matt. 1:1-17). He was prefigured in the Passover (Exod. 12), the offerings in Leviticus 1-5, the Tabernacle, and the Day of Atonement (Lev. 16), just to name a few. Furthermore, He was prophesied by Isaiah, Micah, and many others. Thus, before the coming of Christ, the CONTENT of saving faith (i.e. what someone was to believe in order to be saved) may have been somewhat different (depending on the extent of God’s revelation to that point in history), but the OBJECT of saving faith has always been God and His faithful promises revealed in Scripture. This is why Paul is able to hold up Abraham as a model of faith for the first century Christians in Rome (see Romans 4). As Paul points out, all the way back in Gen. 15:6 we read of Abraham, “Then he believed in the Lord; and He reckoned it to him as righteousness.” In other words, Abraham was saved by grace, through faith, just as we are today.
God bless you,