Matt. 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 the child of the Holy Ghost. 19. Then Joseph, her husband, being a just man, and not willing to make her a publick example, was minded to put her away privily. 20. But while he thought on those things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take 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 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, God is with us. 24. Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife: 25. And knew her not till she had brought forth her firstborn son: and he called his name JESUS. 

What was the requirement for the name of the savior-god? 

Matt. 1: 23. Behold, a virgin shall be with child, and shall bring forth a son, and they shall call his name Emmanuel, which being interpreted, God is with us. 24. Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife: 25. And knew her not till she had brought forth her firstborn son: and he called his name JESUS. 

Note that the requirement in Matthew 1:23 was that the savior-god was to be called Emmanuel, not Jesus, but Joseph named him Jesus in Matthew 1:25. 

Contrast Matthew 1:23 with Luke 1:31. 

Luke 1:26. And in the sixth month [of the pregnancy of Elizabeth with John, who would become John the Baptist] the angel Gabriel was sent from God into a City of Galilee, named Nazareth, 27. To a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin’s name was Mary. ... 30. And the angel said unto her, “Fear not, Mary: For thou hast found favor with God. 31. And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name JESUS. 32. He shall be great, and shall be called the Son of the  highest: and the Lord God shall give unto him the throne of his father, David: 33. And he shall reign over the house of Jacob forever; and of his kingdom there shall be no end.

Isaiah 7:3. Thus said the LORD unto Isaiah, "Go forth now to meet Ahaz... . 4. And say unto him, 'Take heed, and be quiet; fear not, neither be fainthearted, for the two tails of these smoking firebrands, for the fierce anger of Rezin with Syria, and of the son of Remaliah. 5. Because Syria, Ephraim, and the son of Remaliah, have taken evil counsel against thee, saying, 6. 'Let us go up against Judah, and vex it, and let us make a breach therein for us, and set a king in the midst of it, even the son of Tabeal.' 7. Thus said the LORD God, "It shall not stand, neither shall it come to pass." 

Isaiah 7: 10. Moreover, the Lord spake again unto Ahaz, saying, 11. Ask thee a sign of the Lord thy God; ask it either in the depth, or in the height above. 12. But Ahaz said, I will not ask, neither will I tempt the Lord. 13. And he said, Hear ye now, O house of David; Is it a small thing to you weary men, but will ye weary my God also? 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. 15. Butter and honey shall he eat, that he may know to refuse the evil, and choose the good. 16. For before the child shall know to refuse the evil, and choose the good, the land that thou abhorrest shall be forsaken of both her kings. 

Notice the requirement to call the babe Immanuel; but contrast that with the requirement to call the babe Mahershalalhashbaz. 

Isaiah 8:1. Moreover, the Lord said unto me, Take thee a great roll, and write in it with a man's pen concerning Mahershalalhashbaz. 2. And I [Isaiah] took unto me faithful witnesses to record, Uriah the priest, and Zeckariah the son of Jeberechian. 3. And I went unto the prophetess; and she conceived, and bare a son. Then said the Lord unto me, Call his name Mahershalalhashbaz. 

Was Ahaz protected from Rezin and Pekah? 

Isaiah 7:1. And it came to pass in the days of Ahaz the son of Jotham, the son of Uzziah, king of Judah, that Rezin the king of Syria, and  Pekah the son of Remiliah, king of Israel, went up towards Jerusalem to war against it, but could not prevail against it. 

2 Kings 16:5 Then Rezin king of Syria and Pekah the son of Remaliah, king of Israel, came up to Jerusalem to make war; and they besieged Ahaz but could not overcome him. 

Or was Ahaz not protected from Rezin and Pekah? 

2 Chronicles 28:5-6 Therefore the LORD his God delivered him (Ahaz) into the hand of the king of Syria. They defeated him, and carried away a great multitude of them as captives, and brought them to Damascus. Then he was also delivered into the hand of the king of Israel, who defeated him with a great slaughter.

Matt. 2:23. [Joseph, Mary and Jesus resided in Egypt to wait until the death of Herod to return to Israel, and upon hearing of the death of Herod, who had sought to kill Jesus, Joseph departed from Egypt and settled with Mary and Jesus in Galilee.] And he [Jesus] 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.

Moreover, there is a controversy regarding whether or not the site/location/settlement/town/city now occupied by the Israeli town of Nazareth was called by the NAME Nazareth in Jesus' time, for the current Israeli town was named Nazareth in the time period of 200 A.D. to 400 A.D. to satisfy Christian pilgrims who expected there to be a Nazareth in Israel.