John Gill Commentary 1 Samuel 12:25

"But if ye shall still do wickedly, ye shall be consumed, both ye and your king." — 1 Samuel 12:25 (ASV)

But if you shall still do wickedly
Continue to rebel against God, revolt from him, and depart from his worship, and despise his prophets, and serve idols:

you shall be consumed, both you and your king ;
their king would be so far from protecting, that he should perish with them, be killed by the sword, as Saul their first king was, or go into captivity, as others of their kings did.