And now it came to pass that according to our record, and we know our record to be true, for behold, it was a just man who did keep the record-- for he truly did many miracles in the name of Jesus; and there was not any man who could do a miracle in the name of Jesus save he were cleansed every whit from his iniquity (3 Nephi 8:1)
I once encountered a criticism that this verse is in error, as one can perform a false miracle, and that Joseph Smith was being naive here. Notwithstanding, the teaching contained in this verse is consistent with the New Testament. In Mark 9:38-40, we read the following:
And John answered him, saying, Master, we saw one casting out devils in thy name, and they followeth not us: and we forbad him, because he followeth not us. But Jesus said, Forbid him not: for there is no man which shall do a miracle in my name, that can lightly speak evil of me. For he that is not against us is on our part. (Mark 9:38-40)
Let us quote two popular Reformed commentators on this passage:
John Calvin, Harmony of the Gospels of Matthew, Mark, and Luke
39. Forbid him not. Christ did not wish that he should be forbidden; not that he had given him authority, or approved of what he did, or even wished his disciples to approve of it, but because, when by any occurrence God is glorified, we ought to bear with it and rejoice. Thus Paul, (Philippians 1:18,) though he disapproves of the dispositions of those who used the Gospel as a pretense for aggrandizing themselves, yet rejoices that by this occurrence the glory of Christ is advanced. We must attend also to the reason which is added, that it is impossible for any man who works miracles in the name of Christ to speak evil of Christ, and therefore this ought to be reckoned as gain; for hence it follows, that if the disciples had not been more devoted to their own glory than anxious and desirous to promote the glory of their Master, they would not have been offended when they saw that glory heightened and enlarged in another direction. And yet Christ declares that we ought to reckon as friends those who are not open enemies.
40. For he who is not against us is for us. He does not enjoin us to give a loose rein to rash men, and to be silent while they intermeddle with this and the other matter, according to their own fancy, and disturb the whole order of the Church: for such licentiousness, so far as our calling allows, must be restrained. He only affirms that they act improperly, who unseasonably prevent the kingdom of God from being advanced by any means whatever. And yet he does not acknowledge as his disciples, or reckon as belonging to his flock, those who hold an intermediate place between enemies and friends, but means that,. so far as they do no harm, they are useful and profitable: for it is a proverbial saying, which reminds us that we ought not to raise a quarrel till we are constrained.
Matthew Henry, Mark
2. The rebuke he gave to them for this (v. 39); Jesus said, "Forbid him not, nor any other that does likewise." This was like the check Moses gave to Joshua; Enviest thou for my sake? Note, That which is good, and doeth good, must not be prohibited, though there be some defect or irregularity in the manner of doing it. Casting out devils, and so destroying Satan's kingdom, doing this in Christ's name, and so owning him to be sent of God, and giving honour to him as the Fountain of grace, preaching down sin, and preaching up Christ, are good things, very good things, which ought not to be forbidden to any, merely because they follow not with us. If Christ be preached, Paul therein doth, and will rejoice, though he be eclipsed by it, Phil. i. 18. Two reasons Christ gives why such should not be forbidden. (1.) Because we cannot suppose that any man who makes use of Christ's name in working miracles, should blaspheme his name, as the scribes and Pharisees did. There were those indeed that did in Christ's name cast out devils, and yet in other respects were workers of iniquity; but they did not speak evil of Christ. (2.) Because those that differed in communion, while they agreed to fight against Satan under the banner of Christ, ought to look upon one another as on the same side, notwithstanding that difference. He that is not against us is on our part. As to the great controversy between Christ and Beelzebub, he had said, He that is not with me is against me, Matt. xii. 30. He that will not own Christ, owns Satan. But as to those that own Christ, though not in the same circumstances, that follow him, though not with us, we must reckon that though these differ from us, they are not against us, and therefore are on our part, and we must not be any hindrance to their usefulness.