1 Kings 13:3

He gave a sign - A sign of this kind - an immediate prophecy to prove the divine character of a remote prophecy - had scarcely been given before this. In the later history, however, such signs are not unfrequent (compare 2 Kings 19:29; Isaiah 7:14).

The ashes ... shall be poured out - i. e., “The half-burnt remains of the offerings shall be ignominiously spilled upon the ground.”