That it may be fulfilled (ινα πληρωθη). Alford says that "it is impossible to interpret ινα in any other sense than in order that." That was the old notion, but modern grammarians recognize the non-final use of this particle in the Koine and even the consecutive like the Latin ut. Some even argue for a causal use. If the context called for result, one need not hesitate to say so as in Mark 11:28; John 9:36; 1 John 1:9; Revelation 9:20; Revelation 13:13. See discussion in my Grammar of the Greek New Testament in the Light of Historical Research, pp. 997-9. All the same it is purpose here, God's purpose, Matthew reports the angel as saying, spoken "by (υπο, immediate agent) the Lord through (δια, intermediate agent) the prophet."

"All this has happened" (τουτο δε ολον γεγονεν, present perfect indicative), stands on record as historical fact. But the Virgin Birth of Jesus is not due to this interpretation of Isaiah 7:14. It is not necessary to maintain (Broadus) that Isaiah himself saw anything more in his prophecy than that a woman then a virgin, would bear a son and that in the course of a few years Ahaz would be delivered from the king of Syria and Israel by the coming of the Assyrians. This historical illustration finds its richest fulfilment in the birth of Jesus from Mary. "Words of themselves are empty. They are useful only as vessels to convey things from mind to mind" (Morison). The Hebrew word for young woman is translated by virgin (παρθενος), but it is not necessary to conclude that Isaiah himself contemplated the supernatural birth of Jesus. We do not have to say that the idea of the Virgin Birth of Jesus came from Jewish sources. Certainly it did not come from the pagan myths so foreign to this environment, atmosphere and spirit. It is far simpler to admit the supernatural fact than try to explain the invention of the idea as a myth to justify the deification of Jesus. The birth, life, and death of Jesus throw a flood of light on the Old Testament narrative and prophecies for the early Christians. In Matthew and John in particular we often see "that the events of Christ's life were divinely ordered for the express purpose of fulfilling the Old Testament" (McNeile). See Matthew 2:15; Matthew 2:23; Matthew 4:14-17; Matthew 8:17; Matthew 12:17-21; Matthew 13:25; Matthew 21:4; John 12:38; John 13:18; John 19:24; John 19:28; John 19:36.