Maher Shalal Hash Baz was a son of Isaiah and his wife, (the prophetess). His name was a prophecy given by God, literally meaning "In making speed to the spoil he hastens the prey". In other words, this was a warning to Syria and Israel (the northern kingdom) that they would soon be destroyed by the armies of Assyria. Asides from his literary significance for the Book of Isaiah little is known about his actual life.
More so than usual, the meaning of the name is important. Like "Immanuel" in the previous chapter, Maher-Shalal-Hash-Baz is a prophecy, a sign from God. The message shifts from God being present to the consequences of Him being forgotten. Syria and Israel had allied against Judah, so they were going to suffer defeat at the hands of a common enemy: Assyria. The long name is four words: Speeding-to the spoil-hastens-the prey.
Isaiah had been called to be a prophet just as a new king rose to power in Judah. The long and prosperous reign of Uzziah had ended, and his son Ahaz needed a word from God. The new king had a problem with bowing to the authority of God, and refused to ask for a sign to confirm Isaiah's first word to him.Isaiah received a word anyway, given not to the king, but to all kings of David's line: a child would be born, to be called Immanuel (Heb: God is with us).
As the Assyrian threat grew, Isaiah was told to act out a prophecy in an unusual way. He was commanded to write out the name on a large tablet, in the common script; making it readable by the masses. He then went into his wife and she gave birth to a son to be named "Maher-Shalal-Hash-Baz". A long name, but as a constant reminder to all the royal court that invasion was coming within two or three years. The invading armies would make swift work of pillaging the towns and cities, taking everything they wanted.
In late 734 BC (or early 733 BC), a child was born at the prophet's home. God had told Isaiah that the destruction would be done before the child was able to speak Eight days later, when he was named, those in attendance were doubtless astonished. At that time his father could remind everyone that though the enemy was coming upon them, God would be with them.
As Maher-Shalal-Hash-Baz and his brother Shear-Jashub ("a remnant will return") grew up, the tension built in Judah. The Assyrian army had devastated the northern kingdom in 732 BC. From his birth, Isaiah recongized his son as a symbolic message for the people of Judah. Taxes increased on the people to provide money to Assyria to keep the Empire from destroying Judah as well. When he was ten or eleven years old, most of the people of the Northern Kingdom (Israel) were taken into captivity. For the most part, things remained quiet as his father continued to prophesy concerning Judah and the neighboring nations.
Nothing is known of him as an adult. Ahaz the king would die and Hezekiah would replace him. This king would boldly stand against the tyranny of Assyria, even as that kingdom sent armies in to destroy Jerusalem. Under siege, it is probable that a 30 year old "Maher" ("Speedy"??) would stand by his father's side with his older brother. The remnant within the walls survived as God sent his angelic hosts to kill the sleeping army of Sennacherib, leaving the night shift to flee with word of disaster to their homeland.
The evil king Manasseh, the son of Hezekiah, is thought to have killed Isaiah. But nothing is known of the fate of his family.
Maher Shalal Hash Baz only appears as a brief symbol, through his name in the book of his father's visions. It seems that both Maher Shalal Hash Baz and his brother, Shear-jashub were named symbolically to communicate a message to Judah. This is very similar to God having Hosea name his children, Lo-Ammi, Lo-Ruhamah and Jezreel .