The people of Nineveh believed God; and they proclaimed a fast, and put on sackcloth, from the greatest of them even to the least of them.
Before leaving this verse, we should note that the first step in the conversion of the Ninevites was their "belief in God."  As, noted above, this refers to a genuine, deep-seated, and sincere conviction that God is God and that all of our allegiance is owed to him.  The New Testament evangelists referred to it as "believing with all of one's heart."  (Acts 8:37 @@AV). It may be feared, as Butler thought, that: