Elder Marion G. Romney
Third, find out whether the worker of the purported miracle has himself received the gift of the Holy Ghost through the prescribed ordinances. If he has not, then his works, whatever they may be, are not the manifestations of the Holy Spirit. This is a key test because, as we have already pointed out, the gifts of the spirit are given by the power of the Holy Ghost. Without the gift of the Holy Ghost, the manifestations of his gifts may not be enjoyed. The Prophet Joseph Smith states this foundation doctrine as follows:
We believe in the gift of the Holy Ghost being enjoyed now, as much as it was in the Apostles' day; we believe that it [the gift of the Holy Ghost] is necessary to make and to organize the priesthood, that no man can be called to fill any office in the ministry without it; we also believe in prophecy, in tongues, in visions, and in revelations, in gifts, and in healings; and that these things cannot be enjoyed without the gift of the Holy Ghost. (History of the Church, Vol. V, p. 27.)
Thus one who has never received the gift of the Holy Ghost cannot possibly work miracles by his power.
Jeffrey R. Holland, “‘Sanctify Yourselves’,” Liahona, Jan 2001, 46–49
…there is no neutral ground in the universe: every square inch, every split second, is claimed by God and counterclaimed by Satan
Teachings of Joseph Smith
The sick may be healed through faith and the exercise of priesthood power, according to the Lord’s will.
“What is the sign of the healing of the sick? The laying on of hands is the sign or way marked out by James, and the custom of the ancient Saints as ordered by the Lord, and we cannot obtain the blessing by pursuing any other course except the way marked out by the Lord [see James 5:14–15].”
James 5:14-15
14 Is any sick among you? let him call for the elders of the church; and let them pray over him, anointing him with oil in the name of the Lord:
15 And the prayer of faith shall save the sick, and the Lord shall raise him up; and if he have committed sins, they shall be forgiven him.
I do believe that we can work miracles if all the requirements have been met..but it is through God, at His instruction and His will.James E. Talmage Articles of Faith
Page 211
“Satan has shown himself to be an accomplished strategist and a skillful imitator; the most deplorable of his victories are due to his simulation of good, whereby the undiscerning have been led captive. Let no one be deluded with the thought that any act, the immediate result of which appears to be benign, is necessarily productive of permanent good. It may serve the dark purposes of Satan to play upon the human sense of goodness, even to the extent of healing the body and apparently of thwarting death.”