When John sent from his prison to know if Jesus was indeed the expected Messiah, Jesus had the messengers stand by while He was healing the people, raising the dead, and doing mighty works. Then He said to them, "Go your way, and tell John what things you have seen and heard; how that the blind see, the lame walk, the lepers are cleansed, the deaf hear, the dead are raised, and to the poor the Gospel is preached." (Luke 7:22)
But Jesus is not the only one who works miracles. The spirits of devils do them also: "For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty." (Revelation 16:14)
False Christs and false prophets work miracles to deceive: "For there shall arise false Christs, and false prophets, and shall show great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect." (Matthew 24:24) "And he exercises all the power of the first beast before him, and causes the earth and them which dwell therein to worship the first beast, whose deadly wound was healed. And he does great wonders, so that he makes fire come down from heaven on the earth in the sight of men, And deceives them that dwell on the earth by the means of those miracles which he had power to do in the sight of the beast; saying to them that dwell on the earth, that they should make an image to the beast, which had the wound by a sword, and did live." (Revelation 13:12-14) "And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the mark of the beast, and them that worshiped his image." (Revelation 19:20)
Miracles by themselves, therefore, are not necessarily a proof of one's Divine authority; and Christ did not depend on them alone to test His Divine mission. "Unto the poor the Gospel is preached." (Luke 7:22)
It was by His words, more than by His miracles, that men were convinced. The rough soldiers who were sent to seize Him, said, "Never man spoke like this Man." (John 6:46)
And so we are thrown back upon the word as the only test. If the ones who perform great signs and wonders are in any point opposed to the plain word of God,--if they seek in any degree to weaken its force, or to show that it does not mean what it says,--know at once that they are not of God. "To the law, and to the testimony; if they speak not according to this word, it is because there is no light in them." (Isaiah 8:20)--Present Truth, May 24, 1894--Timeline: IV-31 (The Inquiry by John's Disciples)--Luke 7:22.