1. What Matthew would say in the gospel of Matthew? Jesus is the Christ who was predicted to come in the Old Testament.
    Mt 1:1, 16, 18-23, Isa 7:14, Mt 2:3-5, Mic 5:2, Mt 2:13-15, Hos 11:1, Mt 2:22-23, Isa 11:1

The Gospel of Matthew was written for the Jews. Matthew testifies to the Jews in the Gospel of Matthew that Jesus is the Christ prophesied in the Old Testament.

Matthew begins the Gospel of Matthew by revealing that Jesus came as the Christ who would come as the descendant of Abraham and David. (Mt 1:1, 16)

Mt 1:1 The book of the generation of Jesus Christ, the son of David, the son of Abraham.
16 And Jacob begat Joseph the husband of Mary, of whom was born Jesus, who is called Christ.

Also, in the Old Testament, it was prophesied that Christ would be born from a virgin body, and Jesus was born from a virgin body according to this prophecy. (Mt 1:18-23, Is 7:14)

Mt 1:18 Now the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost.
19 Then Joseph her husband, being a just man, and not willing to make her a public example, was minded to put her away privily.
20 But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost.
21 And she shall bring forth a son, and thou shalt call his name Jesus: for he shall save his people from their sins.
22 Now all this was done, that it might be fulfilled which was spoken of the Lord by the prophet, saying,
23 Behold, a virgin shall be with child, and shall bring forth a son, and they shall call his name Emmanuel, which being interpreted is, God with us.

Is 7:14 Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.

Also, in the Old Testament, it was prophesied that Christ would be born in Bethlehem, and Jesus was born in Bethlehem according to this prophecy. (Mt 2:3-5, Mic 5:2)

Mt 2:3 When Herod the king had heard these things, he was troubled, and all Jerusalem with him.
4 And when he had gathered all the chief priests and scribes of the people together, he demanded of them where Christ should be born.
5 And they said unto him, In Bethlehem of Judaea: for thus it is written by the prophet,

Mic 5:2 But thou, Bethlehem Ephratah, though thou be little among the thousands of Judah, yet out of thee shall he come forth unto me that is to be ruler in Israel; whose goings forth have been from of old, from everlasting.

Also, in the Old Testament, it was prophesied that God would call Christ out of Egypt, and Jesus will come to Israel after being in Egypt according to this prophecy. (Mt 2:13-15, Hos 11:1)

Mt 2:13 And when they were departed, behold, the angel of the Lord appeareth to Joseph in a dream, saying, Arise, and take the young child and his mother, and flee into Egypt, and be thou there until I bring thee word: for Herod will seek the young child to destroy him.
14 When he arose, he took the young child and his mother by night, and departed into Egypt:
15 And was there until the death of Herod: that it might be fulfilled which was spoken of the Lord by the prophet, saying, Out of Egypt have I called my son.

Hos 11:1 When Israel was a child, then I loved him, and called my son out of Egypt.

Also in the Old Testament it was prophesied that Christ would be called a Nazarene, and Jesus lived in the town of Nazareth according to this prophecy. (Mt 2:22-23, Isa 11:1)

Mt 2:22 But when he heard that Archelaus did reign in Judaea in the room of his father Herod, he was afraid to go thither: notwithstanding, being warned of God in a dream, he turned aside into the parts of Galilee:
23 And he came and dwelt in a city called Nazareth: that it might be fulfilled which was spoken by the prophets, He shall be called a Nazarene.

Isa 11:1 And there shall come forth a rod out of the stem of Jesse, and a Branch shall grow out of his roots: