What does Isaiah 7:12 mean?

Ahaz has been told to trust the Lord. He has been reassured, to not be afraid about the nearing threat from the kings of Syria and Israel (Isaiah 7:4–6). Though it is not discussed in this passage, the Lord wants Ahaz to trust Him instead of turning to the king of Assyria for help in fighting Judah's enemies (2 Kings 16:7–9).

To prove He is with Ahaz and His power is real, the Lord has commanded Ahaz to ask for a "sign." This means a miraculous, supernatural demonstration of the power of the Lord (Isaiah 7:11). Through Isaiah, the Lord has even emphasized that there will be no limits on the sign Ahaz can request. It could be anything that would bring Ahaz the peace of mind that God's power was at work in this moment for him and for Judah.

Yet Ahaz says no. His response is framed as if he has passed an experiment on his faith, saying he will not "put the Lord to the test." He quotes from Deuteronomy 6:16, where God commands Israel not to test Him. That passage, though, is about testing God's patience and mercy in rebellion fueled by doubt or faithlessness. Jesus also quotes this verse in answer to one of the temptations from Satan to demonstrate His supernatural power before God's timing (Luke 4:12).

Neither scenario applied to Ahaz. While asking God for miraculous proof expresses a lack of faith, Ahaz was not the one who made the request. Rather, God told him to ask for sign. That makes his refusal, and God's response, points to consider when understanding the passage. Taken together, it seems Ahaz isn't expressing faith, but stubbornness. What's implied in this passage is that the king's mind is already made up. He doesn't want to be distracted by supernatural displays of God's power through the prophet Isaiah. He wants to produce the answer himself. And he will do that by putting the fate of his nation in the hands of the powerful Assyrian king (2 Kings 16:7–9).