From the Word
17 And these signs will accompany those who believe: in my name they will cast out demons; they will speak in new tongues; 18 they will pick up serpents, and if they drink any deadly thing, it will not hurt them; they will lay their hands on the sick, and they will recover.”
Mark 16:17–18, RSV
How shall we proceed here that we may preserve the truth of this passage? The Lord says all these signs shall accompany them. Now we know that the apostles did not present all the signs, and if the passage shall stand literally, then few believers will be cleared and few saints be entitled to heaven; for these signs, one and all, have not accompanied them, though they have had power to work signs, and have exhibited some of them. These words, therefore, do not refer to the Church as a whole, but to persons separately. If there is a Christian who has faith, he shall have power to do these accompanying miracles, and they shall follow him. Christ says, “He that believeth on me, the works that I shall do, shall he do also.” The Lord has given Christians power also against the unclean spirits. There was once a patriarch in the wilderness, who, when he met a serpent, took it in both hands and tore it in two, saying, What a fine thing it is to have a clear and guiltless conscience. So, where there is a Christian, there is still the power to work these signs if it is necessary.
But no one should attempt to exercise this power if it is not necessary. The apostles did not always exercise it, but only made use of it to prove the Word of God, to confirm it by miracles. “They went forth and preached everywhere, the Lord working with them, and confirming the Word with signs following.” Since the gospel has now been spread abroad, and made known to all the world, there is no need of working miracles as in the apostles’ time. Then let no one without pressing need undertake to work wonders. I know not what I shall say about those who venture to do signs where they are not necessary. I know that it is a dangerous undertaking. The devil, indeed, lets himself be driven out, but he does not intend to suffer for it; he allows it only that he may strengthen the sign-worker in such error. I would not like to trust him. But wherever a Christian dies in Christ with cheerful heart, Satan has been truly cast out and deprived of his power and kingdom.
Luther, Martin, and John Sander. Devotional Readings from Luther’s Works for Every Day of the Year. Augustana Book Concern, 1915, pp. 173–74.