What does Isaiah 5:24 mean?
Isaiah has been describing the outcome for those who blatantly disregard the Lord. He has identified them as people who intentionally carry their sin around with them (Isaiah 5:18). They have mocked God's coming judgment (Isaiah 5:19) and turned good and evil upside down (Isaiah 5:20). Lastly, He has condemned those who are praised for their drinking while taking bribes to set guilty men free (Isaiah 5:23).These people will be like a plant that is so dried out, it instantly ignites all the way down to the root when it is touched by fire. The plant has become rotten to the core. It is obliterated the moment fire catches it. Those in Israel who have forsaken the Lord and His word should expect to be quickly consumed when the Lord's judgment comes.
That's exactly what the people of Judah had done. They had spat upon God's revelation to them. They had invested in glorifying and satisfying themselves. This had made their existence dangerously temporary.