Like many of the other psalms, the full import of Psalm 78 can only be appreciated once we understand that it points beyond its immediate context. Originally, Asaph wrote this psalm rehearsing the failures of the Israelites in order to convey the importance of handing on the truth of God from generation to generation (vv. 1–3). The examples of unfaithfulness in the past underscored the importance of faithfulness in Asaph’s day and, by extension, the importance of faithfulness in our own generation (vv. 4–66; 1 Cor. 10:6). Yet the significance of this psalm is not exhausted as a call for us to be faithful based on the negative examples of the ancient covenant community. Instead, the ending of this psalm with its rehearsal of the anointing of David points forward to David’s greater son, Jesus Christ.
Simply put, Psalm 78 is a messianic psalm. As we consider the progression of events in the psalm, we see that the record of Israel’s unfaithfulness ends abruptly with David. With the rejection of Ephraim, the tribe of Joshua, a prominent leader of God’s people (Num. 13:8, 16), it was made clear that Judah should be the head tribe in Israel (Ps. 78:67–68). This, of course, was a fulfillment of Jacob’s ancient prophecy (Gen. 49:10). Moreover, as already noted, the reign of King David of Judah did mark a significant departure from Israel’s earlier wickedness. There was not the same widespread problem of idolatry during David’s reign that marked the generations in the time leading up to his ascension.
However, David’s rule was not without problems. His adultery led to great upheaval, and his successor, Solomon, allowed idolatry to flourish in the nation again (2 Sam. 11–24; 1 Kings 11). As good as David was, he was not the king to secure the faithfulness of God’s people.
Thus, the psalm fosters hope that after Israel’s unfaithfulness, a new David will rise, a king to rule in perfect righteousness. Like David, who was a shepherd of humble origin (Ps. 78:70), this king will come from inauspicious beginnings to lead God’s people “with upright heart” and “skillful hand” (v. 72). Like David, this new, humble king will rely not on others to usher in the kingdom but on God alone. We know that this king is Christ, whose kingdom was inaugurated not with military force but through the death of the cross. John Calvin comments, “It was requisite that the commencement of the kingdom of Christ should be lowly and contemptible, that it might correspond with its type, and that God might clearly show that he did not make use of external aids in order to accomplish our salvation.”