The nation of Israel was formed by God with a prophet, chosen by him, to stand at its head. The law of Moses, which governed the nation, was given by revelation and could only be amended in the same manner. It was the divine intent that Israel always be led by prophets. This being the case, it was essential that citizenry of the nation be able to discern between the true and the false prophet.
To that end Moses, the first prophet to the nation of Israel, established the first scriptural test by which prophets were to be discerned. “When a prophet speaketh in the name of the Lord,” he said, “if the thing follow not, nor come to pass, that is the thing which the Lord hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him” (Deuteronomy 18:22). We could hardly be expected to reverence as a prophet one whose prophecies fail to come to pass.