Charles Ellicott Commentary 1 Kings 20:22

"And the prophet came near to the king of Israel, and said unto him, Go, strengthen thyself, and mark, and see what thou doest; for at the return of the year the king of Syria will come up against thee." — 1 Kings 20:22 (ASV)

The return of the year. — The early part of the next year, after the winter was over, when kings go out to battle (2 Samuel 11:1).