Maher-shalal-hash-baz's mother was the wife of the prophet Isaiah. God commanded Isaiah to write,
Belonging to Maher-shalal-hash-baz [swift is the plunder; speedy is the prey] on it. After Isaiah's wife conceived and gave birth to a son, God commanded Isaiah to name him "Maher-shalal-hash-baz". The tablet and the son's name became testaments of God's prophecy: the Assyrians were going to plunder Damascus and Samaria.
Then the Lord said to me,Take for yourself a large tablet [for public display] and write on it in ordinary characters: Belonging to Maher-shalal-hash-baz. And I will get faithful witnesses to attest [to this prophecy] for me, Uriah the priest and Zechariah the son of Jeberechiah.So I approached [my wife] the prophetess, and she conceived and gave birth to a son. Then the Lord said to me,Name him Maher-shalal-hash-baz [to remind the people of the prophecy]; for before the boy knows how to say,My fatherorMy mother,the riches of Damascus (Aram’s capital) and the spoil of Samaria (Israel’s capital) will be carried away by the king of Assyria.— Isaiah 8:1–8:4 (AMP)
And God's prophecy came true; the Assyrians, under Tiglath-Pileser III, plundered Damascus and Samaria.