Imagine for a moment....
While Jesus is living and teaching among the Jews, everyone in that region becomes aware of his teaching, and his claims of deity as the Son of God and promised "Anointed One". But during the period of three days after Jesus' death, rumors spread about his death. Every faithful Jew, hoping for the consolation of Israel and the coming of the Kingdom of heaven, is somewhat disappointed that their promised Messiah is dead.
Shortly thereafter, some disappointed Jews are traveling on a road about seven miles outside Jerusalem, and there they encounter a stranger; and they have a conversation with him about their doubts in this promised Messiah, Jesus. After a while, the stranger decides to assert his opinion about the present circumstances and all of their doubts, saying "O foolish ones, and slow of heart to believe all that the prophets have spoken! Was it not necessary that the Anointed One should suffer these things and enter into his glory?" This intrigued them very much, and so they invited the stranger to sit down and share a meal with them to talk more. The stranger thought them to be very considerate, so they all found a place to eat and discuss the Scriptures together.
Not too long after discussing these and other important issues concerning the consolation of Israel, a startling circumstance occurred. After everything important had been being said, the stranger broke some bread -- literally -- and vanished. But that's not all! Not only did the stranger vanish; their eyes were then opened to understand who he was and what he was teaching them about the relationship between the God, Israel, and the world which Jesus saved. And so, as anyone as excited as them would do, the men who witnessed this amazing revelation rushed back to Jerusalem that night to tell Jesus' disciples their story and all they had learned.
Much to everyone's surprise that evening, while the eleven disciples were learning what happened earlier in that day, Jesus appears before all of them, even the men before whom he vanished, and startles them. His words were not many, but what was spoken was received well because it was to the point. And one of the most important things Jesus said to them that night was this:
These are my words which I spoke to you while I was still with you, that everything written about me in the Law of Moses and the Prophets and the Psalms must be fulfilled.
Imagine further, that shortly after Christ's resurrection, one of Jesus' disciples who was well educated and highly literate (and probably very organized and detail oriented because he was a tax collector around Palestine for many years) was also commissioned to write a story about Jesus to his brethren in Palestine; and the purpose of that story was to declare that everything written about Jesus in the Law of Moses, the Prophets, and the Psalms must be fulfilled, just as Jesus had told them before.
And so, seeing the immense importance of this commission, and his qualifications for accomplishing his task, he compiles all of his notes. He then sets out to learn from many other eye-witnesses some further testimonies of what Jesus did. Before long, he realizes that he is confronted with a huge dilemma: If he were to write a story about all the things that Jesus did, the world itself could not contain the books that would be written. And so he prays about his task at hand and he seeks wise counsel from the other apostles and elders. Their advise for him was to narrow the focus of his epistle in a way which is clearly intended for his brethren in Israel (as commissioned) and clearly not addressed to everyone in the world, as though every single thing Jesus said in context had to be addressing people on continents not yet discipled and knew nothing about Israel's expectations; but rather, they advised, because his commission was to minister to the lost sheep of the House of Israel within the promised land, he should tell the story of Jesus' life to them in a way which they will vividly understand, in a way which is first and foremost relevant to them and their history, not to gentiles ten-thousand miles away. And so he though about their advise for a long time and eventually went home to pray and think about ways to implement their wise insights.
It didn't take long after prayer before he received the revelation he longed for. He recalled that the whole history of Israel was more than just a story about a chosen people in need of a Savior. They were a type of firstborn son, whose genealogy begins with a call out of Egypt into God's rest. They were a royal priesthood, a holy nation who received the revelation from their Heavenly Father at Mount Sinai, who wandered in a wilderness for forty years before entering the inheritance He had promised them as His "son". They were a people who crossed the river Jordan and eventually conquered the land which God promised for them, only to learn the hard way, as years went by, that their own foolishness and spiritual harlotry displeased their Father and earned their disinheritance for a time. But their Father was indeed merciful, especially as they pleaded to Him for wisdom. He gave them wisdom and He gave them a King after His own heart to rule over them. But that didn't last forever either. Only after three kings sat on the throne of Israel, the kingdom was divided and their inheritance was seeing a steady decline as well. Eventually Judah, the land of God's dwelling place in their midst, and the House of Israel would reach a definitive end, being transported into Babylonian captivity. The story of God's House in Jerusalem being destroyed and His people going into captivity was the point of Israel's death.
But according to the everlasting Covenant of God, and His enduring mercies every day, the Father provided a resurrection for his "son", Israel. Israel's resurrection came within the greater Egypt, the land of Babylon, after the influence of Daniel but before the great decree of Cyrus, king of Persia, who eventually ruled over the land of Babylon. Cyrus, the Lord's anointed, recognized that the Lord who raised up Israel under his reign and given them life once again, had given him the responsibility to send them out into the world and rebuild His House. And so, Cyrus gave Israel this great commission:
Thus says Cyrus king of Persia, "The Lord, the God of heaven, has given me all the kingdoms of the earth, and he has charged me to build him a house at Jerusalem, which is in Judah. Whoever is among you of all his people, may the Lord his God be with him. Let him go up!
Then it clicked in Matthew's mind: he should tell the story of Jesus-as-Israel; then the people of Israel would understand that Jesus is the promised Messiah, the one-of-a-kind Son of God that fulfilled everything written about him in the Law of Moses, the Prophets, and the Psalms.