Therefore every scribe who has been trained for the kingdom of heaven is like a master of a house, who brings out of his treasure what is new and what is old (Mt. 13.52 ESV)

Peter Williams demonstrates some of the ways Christians are to harmonize the Testaments. He discusses implicit and inherent allusions in the parable of The Prodigal Son[s]. Of course, the N.T. either quotes or alludes to texts in the O.T. explicitly about 300 times.

I would like to add this interesting thought, not discussed in the video: In the parable the analogy of the younger son is the repentant people in Jesus’ day, including those who had previously lived reckless lives for one reason or another. The older son signals the religious leaders who didn’t want to spend time with the Father (Whom Jesus perfectly represented), but sin with their own kind. The younger son in the parable only had the gifts from his father while the whole estate belonged to the older son. He had it all, yet begrudged a destitute brother his favor in a family meal. This seems an apt characterization of this group since they even attested this conceit in council: But this crowd that does not know the law is accursed (Jn. 7.49). Jesus says just the opposite: those who only know the Law are accursed. The function of the Law was to reveal the need for forgiveness and righteousness. It was the Bad News. The term “gospel” refers to the euangelium in Greek. It just means “welcomed announcement” or “good news.” This term references Jesus’ fulfillment of The Law (accepted by the Father in the resurrection and ascension) and His substitution of punishment in our stead. The Good News is : And let the one who is thirsty come; let the one who desires take the water of life without price (Rev. 22.17b ESV). This is not slavish obedience in one’s own strength but a free gift.

The 1st and 2nd Temple reflected redemption, which Jesus provided, as explicated so eloquently in Hebrews. However, one first needed to see clearly their own sin; this is exactly what the First Covenant did: For the letter kills, but the Spirit gives life (2Cor. 3.6b ESV). If the Law was all one had, then forgiveness is unattainable since redemption is still needed because all have sinned. Even if one could keep the Law henceforth after failing (which is an impossibility), the previous failure still needs atoning. The temple was destroyed according to Daniel’s prophecy (9.26) which was fulfilled in 70 C.E. The earthly sanctuary, which was a mere representation of heaven’s temple, is no longer needed since Jesus served in the true one in heaven with His own blood. (see Heb. 8.1-2).

Anyway, the blood of bulls and goats could never take away sin. Instead, Jesus presents a better hope of life in Christ: For on the one hand, a former commandment is set aside because of its weakness and uselessness (for the law made nothing perfect); but on the other hand, a better hope is introduced, through which we draw near to God (Heb.7.18-19 ESV).

Dr. Peter J. Williams | “The Surprising Genius of Jesus” – YouTube