In viewing the bearings of this passage on the credentials of revelation, two points should be observed.

1. The case supposed is one in which the prophet contradicts a revelation already received.

2. The prophet does not dispute the evidence of that earlier revelation. On the contrary, he admits it. He stands within the lines of it. He professes to speak under its authority. Yet he asks the people to violate its fundamental laws. This of itself was sufficient to convict him. His pretensions are disposed of by the simple fact that, professing to speak in the Name of God, he gives the people a message contradictory of what he admits God to have previously revealed. No sign and wonder can accredit contradictions. The prophet is inconsistent with himself, and is not to be listened to. Nay, his message had been anticipated, and the thing he bids the people do, expressly forbidden. Notice, then -

I. EXTERNAL MIRACLES DO NOT OF THEMSELVES ACCREDIT A REVELATION AS FROM GOD. (Vers. 1-3.) This prophet gives a sign or wonder - presumably a predictive word - and it actually comes to pass. The failure of his sign, according to Deuteronomy 18:21, 22, would have been a proof of falsity. The converse of this, however, that he speaks God's word because his sign has not failed, is not immediately to be admitted. There are other tests to be applied. In this case, the prophet's message is condemned because contradictory of what he himself allows to have been a true revelation. This raises the question of the value of miracles as credentials of revelation. That they have a value is not disputed, but not as mere signs and wonders. This will be best seen by contrasting the sign or wonder given by this prophet with the evidence of the earlier revelation. If we take the Scripture account of the founding of the Mosaic dispensation, it is impossible to question the magnificence and convincingness of the displays of Divine power and holiness therein contained. In founding his dispensations (Mosaic and Christian), God has not only given evidence, but an amount and kind of evidence which put the source of the revelation - admitting the facts to be as stated - beyond all cavil. For here, it is not merely the fact of miracle which is to be regarded, but the number, nature, magnitude, variety, spiritual quality of the supernatural events, in connection with the self-evidencing divineness of the revelation itself. The difficulty as to whether the miracle proves the doctrine, or the doctrine the miracle, or in what proportions the two factors combine, has little place in the actual evidences of revelation. The two cannot be separated, either in thought or in fact. Grant the authenticity of the miracles of the Gospels or of the Pentateuch, and it will not be disputed that they originated with God, not with Beelzebub. To this mass of evidence, overwhelming in its sublimity and convincingness - evidence- embracing the wonders of Egypt, the displays of God's power, love, and grace in the events of the Exodus, the miracles of the desert, the stupendous revelations of Sinai, etc. - the prophet opposes a few stray signs and wonders. Which were the people to believe? Plainly, no sign or wonder would have justified an Israelite in believing a prophet whose teaching contradicted the first principles of his revelation; as no sign or wonder would justify us in believing teachings contradictory of the first principles of ours.

II. THE RISE OF FALSE PROPHETS IS TO BE ANTICIPATED. (Ver. 1.) The passage takes it for granted that they will arise. They did arise in Old Testament times, and they will do so again. Their appearance is predicted in connection with "the last days" (Matthew 24:11; 1 Timothy 4:1; 2 Peter 2:1). "Signs and wonders" will not be wanting (Matthew 24:24; 2 Thessalonians 2:9, 10). False teachers are included under the category of false prophets (Matthew 7:15; 2 Peter 2:1). They assert as the truth of God principles and doctrines subversive of the revelation God has given. The readiness of people to believe them arises from want of knowledge (Ephesians 4:14); from the itch for novelties (2 Timothy 4:3); from a diseased craving for the marvelous - witness the credulity displayed in connection with spiritualism (2 Thessalonians 2:9-13); above all, from the adaptation of their teachings to the inclinations of depraved hearts (2 Timothy 3:1-8).

III. THE RISE OF FALSE PROPHETS IS PERMITTED FOR THE SIFTING OF THE CHURCH. (Ver. 3.) God has thus much to do with their appearance that he permits it as a means of proving and sifting the Church. The trial is a searching and real one. The plausibility of their errors may occasion, even to believers, much mental conflict, But out of this conflict they come forth strengthened and purified, with firmer hold upon the truth, and clearer insight into Scripture. Those willing to be deceived are, on the other hand, led by the spirit of delusion. False prophets shake all but "the very elect" (Matthew 24:24). The heresies, schisms, controversies, etc., which have agitated the Church, with the teachings of antichristian philosophy and science outside of it, have always had this effect of sifting, while in the end they have subserved the progress of the truth.

IV. THE TEACHING OF FALSE PROPHETS IS TO BE REJECTED.

1. Their doctrine is to be tried by its conformity with the rule of faith (Isaiah 8:20). John bids us "try the spirits," giving as the reason that "many false prophets are gone out into the world" (1 John 4:1).

2. Their doctrine, if found contradictory of Scripture, is to be unhesitatingly rejected.

3. Of old, the prophet whose teachings struck at the foundations of the theocracy was to be put to death (ver. 5). This rule no longer applies. But it is the duty of the Church, in the exercise of her judicial functions, to deprive such a teacher of office and status in her ministry (see also 2 John 1:10, 11. - J.O.

Israel must conquer idolatrous cities, and destroy all the spoil, regarding all that had been polluted by idolatry as an accursed thing to be burned with fire. Now, sin of all sorts must be treated by Christians in the same manner. We must not allow a single evil habit to remain. It is now war to the knife with sins of all sorts and sizes, whether of the body, the mind, or the spirit. We do not look upon this giving up of evil as deserving mercy, but we regard it as a fruit of the grace of God, which we would on no account miss. When God causes us to have no mercy on our sins, then He has great mercy on us. When we are angry with evil, God is no more angry with us. When we multiply our efforts against iniquity, the Lord multiplies our blessings.

( C. H. Spurgeon.).