In 1 Kings 13-14, the Lord set up a new nation, a new kingdom. That kingdom that came to be was the kingdom of Israel; the Lord rent in two the kingdom of Israel (chapters 11-12) because Solomon was not as his father David.
The kingdom of Israel was led by Jeroboam. The Lord promised him all would be well if he was loyal to the Lord and His revealed will. Jeroboam was not, however. He feared the people and because his fear was so great it led him to do more evil than all before him (1 Kings 14:9).
Three things resulted from this: first, the Lord was against him; second, the Lord was going to bring his kingdom, his heritage to a violent end, third, his first-born son would die a natural death (contrast the second point) because the Lord saw something good in him (14:13). These warnings came from the Lord's prophets.
The Lord's prophets may expound on something in the future, but they mostly expounded on exhortations towards godliness to the people from the king down to all his subjects. If the people refused to listen, then the Lord's prophets told them of the consequences in front of them.
In a New Testament context, preachers do the same. He must preach the word, be urgent in season, out of season, reprove, exhort with all longsuffering. He becomes greatly frustrated on occasion; still, he must stay the course. Some interested soul will listen to the Lord.
Jeroboam refused to listen because his loyalties were with the people, not the Lord. It cost him!