The Birth of ​Isaiah's Son

Isaiah 8:1-4

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 took unto me faithful witnesses to record, Uriah the priest, and Zechariah the son of Jeberechiah. 
3  And I went unto the prophetess; and she conceived, and bare a son. Then said the LORD to me, Call his name Mahershalalhashbaz. 
4  For before the child shall have knowledge to cry, My father, and my mother, the riches of Damascus and the spoil of Samaria shall be taken away before the king of Assyria.