The punishment for disobeying God was swift and decisive, despite his being enticed by the crafty, older prophet. The "senior prophet" should have known much better than to ever challenge God this way and place the life of his younger friend in mortal danger: it seems he was both a scheming liar and a fool.
Nonetheless, this prophet should have known that if God had somehow "changed His mind," He would definitely have conveyed that to the unnamed prophet just as He did with his initial charge - and, much later with the underhanded older man.
The warning we must heed, as Christians today, is the certainty that many pretentious "prophets," those that range from professional religionists to the friendly, neighborhood minister, may suggest every manner of false teaching. *IndeedIndeed, they are oftenthey are often entirely unaware of the fact themselves! These are the ones described by Christ in Matthew's Gospel:
Matthew 7:2115: "Beware of the false prophets, who come to you in sheep's clothing, but inwardly are ravenous wolves."
Just who are these "ravening wolves" if not those who appear so benign and trustworthy? Does it matter whether they seem sincere with their false doctrine, as was perhaps the lying older prophet in 1 Kings 13?