What does Isaiah 8:3 mean?

The sequence of events recorded in this passage is as follows: In the presence of two witnesses, Isaiah obeys the voice of the Lord and writes a specific name on a signboard (Isaiah 8:1). Then he goes home and sleeps with his wife, who is called a prophetess. She becomes pregnant and gives birth to a son.

Some commentators speculate whether Isaiah's first wife had died or that this prophetess is an additional wife. In the previous chapter, which clearly speaking of these same events, Isaiah referred to the woman who would bear this son as a "virgin." This leads to an understanding that she was unmarried at the time (Isaiah 7:14). If that is the case, Isaiah only now takes her as his wife and sleeps with her. This is still consistent with Matthew's application of Isaiah 7:14 to Mary and the birth of Jesus the Messiah (Matthew 1:20–22). Bible scholars call this a "double fulfillment."

It is possible the woman was called a prophetess because she was married to a prophet. Commentators say it is more likely that she also prophesied in Judah on behalf of the Lord. Female prophets are found throughout the Old Testament so this would not come as a surprise to the people of Judah (Exodus 15:20; Judges 4:4; 2 Kings 22:14; Nehemiah 6:14).

Once the boy is born, the Lord tells Isaiah to call the boy the name that he had earlier written on the sign. The boy is the fulfillment of the prophecy built into his name, which translates to "speeding to the plunder, hurrying to the spoil." As well as the continuation of the prophecy of the destruction that the king of Assyria would soon bring into the region.

In Isaiah 7, the prophet had told King Ahaz the baby would be called Immanuel, which means "God with us." The baby was likely called by both names. The name "Immanuel" will come up once more later in this chapter (Isaiah 8:8). This fulfillment of prophecy through the child's birth served as evidence of "God with us."