Several considerations come into play as we try to retrospectively understand how this made sense to Matthew and the earliest Christians. First, Matthew alerts us to the fact that it may not be an exact quotation of a single specific text by saying that it “was spoken by the prophets [plural]” (Matt. 2:23). This opens up the possibility that Matthew is referring to a prophetic theme found in multiple prophets that could best be communicated by the words “he will be called a Nazarene.”
Isaiah 11:1 states, “There shall come forth a shoot from the stump of Jesse, and a branch [neṣer; nṣr in consonantal Hebrew] from his roots shall bear fruit.” There was a whole cluster of messianic texts related to a branch that, although using different Hebrew words, would have been associated with the branch (nṣr) of Isa. 11:1 by first century Jews and Christians (Isa. 4:2; 53:2; Jer. 23:5; 33:15; Zech. 3:8; 6:12). Although it is impossible to know with certainty the original Hebrew meaning of the name Nazareth (likely nṣrt) it likely was quite closely related to “branch” (nṣr) and an English translation might very well call it “Branchville” or “Branchtown.”
Matthew is thus making the following point with this final fulfillment quotation: Jesus’s association with Nazareth was not accidental but was planned by God in order that Jesus would be called a Nazarene, a confirmation of his identity as the prophesied and messianic Davidic branch of Isa. 11:1. This connection is further strengthened by the proximity of Isa. 11:1 with Isa. 7:14, the first fulfillment of Scripture quoted by Matthew in Jesus’s infancy narratives in Matt. 1:23. Matthew would have easily identified the promised branch of Isa. 11:1 with the promised birth of a son in Isa. 7:14 and Isa. 9:6. Nazareth was a small, obscure town (likely consisting of around 500 people) and nobody at the beginning of the 1st century associated it with the Messiah (see Nathanael’s dismissive remark in John 1:46) but looking backwards after the fact Matthew and the other earliest Christians recognized God’s providential care in causing the messianic branch to grow up in Branchville.