Which brings us to the main contention of the New Testament: the cross.[33] For those expecting the Messiah’s kingdom to appear “immediately (Lk. 19:11)”, the death of the one they believed to fill that role was earth shattering.[34] Though John the Baptist seemed to have an inkling (Jn. 1:29), and though Jesus warned them (Matt. 16:21), the sentiment of the apostles was that “this shall never happen (Matt. 16:22)” as the common expectation around Jesus’ life and ministry was “that He was the one to redeem Israel (Lk. 24:21).”
Due to this confusion, we can surmise that this understanding of the necessity of the Messiah’s suffering before eschatological glory was the dominant topic of Jesus post-resurrection teaching (Lk. 24:13-27) and what that young man behind the tree was eavesdropping on. Consider, had Jesus not explained what was happening in His death, how would they know? It was necessary that the Messiah suffer, and it was necessary that He explain what His suffering meant.
To teach the early disciples, Jesus explained the cross via the Levitical system and the direct prophecies of messianic suffering (Is. 53:4-11) found in the Tanakh. As Jews, the disciples understood worshipers in the Levitical system were saved and forgiven by faith through the judgement that falls on the sacrifice (Lev. 17:10-11, 16:20-22).[35]
Thus, after being taught these things, the apostles declared that everyone who believes in Jesus’ cross as a sacrifice for sins will receive forgiveness of sins at the Day of the Lord and inherit eternal life in the Kingdom of God (Ac. 10:42-43).
For the apostles, the sacrificial cross functions as the mechanism for reconciliation[38], whereby those former enemies in Adam who now trust in the sacrifice are at peace with God (Col. 1:19-22) in Christ.
The cross also functions for propitiation (Rom. 3:21-15) to appease God’s right wrath on sin and serves the means by which God justifies and those with trust righteous on the Day of the Lord (Rom. 5:1-9). In the cross and in the blood shed there, those with trust are also redeemed (Eph. 1:4-8) by the ransom Christ paid (Mk. 10:45). Finally, the cross is the means by which both Jew and gentile may inherit the “promised inheritance (Heb. 9:13-15).”[39]
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[33] Erickson, Christian Theology, 740-744.
[34] Fredriksen, Jesus, 265.
[35] Hamilton, God’s Glory, 111.
[36] John Stott, The Cross of Christ (Downers Grove: IVP), 1986, 161.
[37] Erickson, Christian Theology, 741.
[38] Erickson, Christian Theology, 743.
[39] Harrigan, The Gospel of Christ, Loc. 4923.