Matthew 2:5

‘And they said to him, “In Bethlehem of Judaea, for thus it is written through the prophet,”

Whether they were able to answer almost immediately, or whether they had to go into in depth consultation we are not told, but if the latter we can be sure that they took a great deal of trouble about it. For Herod in this mood was not a man to be crossed. Eventually (or possibly even immediately, although if so they probably made the most of it) they were able to give him his answer. According to the prophet it would be in Bethlehem of Judaea. For that was what was written ‘through the prophet' (in Micah 5:2 with a sprinkling of 2 Samuel 5:2). The citation is an amplified translation of combined texts, which may well be why he does not name ‘the prophet'. For such combined texts compare Mark 1:2. The version from which they were taken is not known to us, and it may have been Matthew's (or the Scribes') own paraphrase.

The verse in Micah comes in a context which is dealing with the days when God will finally establish His king in triumph over Jerusalem and the world, after the tribulations that they have been through. The idea is that then will arise the promised Davidic king. Bethlehem was the home of the house of David, and thus the king was seen as necessarily coming from Bethlehem, David's home town. The thought is that small though Bethlehem might be, it had produced a great house (1 Samuel 16:4), the house that God had chosen, and the house through which He would establish His name. Thus as David had come forth from Bethlehem, so would the greater David.