We read this description of false churches in the last days:
2 Nephi 28:5 And they deny the power of God, the Holy One of Israel; and they say unto the people: Hearken unto us, and hear ye our precept; for behold there is no God today, for the Lord and the Redeemer hath done his work, and he hath given his power unto men;
6 Behold, hearken ye unto my precept; if they shall say there is a miracle wrought by the hand of the Lord, believe it not; for this day he is not a God of miracles; he hath done his work.
Why do they preach against miracles?
Because the rights of the priesthood are inseparable connected with the powers of heaven and the powers of heaven cannot be controlled nor handled only on the principles of righteousness.
What that means is that you have to be living the principles of righteousness to work miracles. You cannot be connected to the powers of heaven, by, for example, working miracles, unless you are living sufficiently righteously. There are no exceptions.
D&C 132:5 For all who will have a blessing at my hands shall abide the law which was appointed for that blessing, and the conditions thereof, as were instituted from before the foundation of the world.
There are larger and smaller ways these can be manifest. One miraculous event we do see commonly is to see the gift of the Holy Ghost bestowed on a person through the priesthood after baptism.
But we live far beneath our privileges.
Living far beneath our privileges is dangerous stuff.
Why? Because it is when we live far beneath our privileges that we cannot discern the truth in a way that is similar to the way Moses did.
If we are well acquainted with the Holy Ghost than it is relatively easy to recognize when we do something that goes against the commandments. We can recognize the Holy Ghost's departure. We see the way our spiritual blessings depart. We notice that we cannot discern things through the light of Christ. We feel cut off. We experience significantly less of God's grace because we have cut ourselves off from it for a time.
But if we are not well acquainted with the Holy Ghost, we are like a blind person. If we are in the regular habit of offending the Holy Ghost by our actions (in these days, particularly by our media) then we do not notice a significant change when he is driven away.
Harold B Lee said rightly that the only safety is living so that we have the Holy Ghost.
The more we live beneath our privileges, the more dangerous our position is.
That is partly because the adversary is happy to fill in when the Holy Ghost is not present. We see the world being driven by the adversary as a dumb beast wherever he wills. When we don't have the Holy Ghost, we needn't wonder whether anyone else will be willing to fill in for him in his absence. The adversary always steps in when we drive away the Holy Ghost.
So the only safety is to live to have the Holy Ghost. It is to do all we can to keep the commandments and come more and more in time under the power of God and more out more in time out from under the influence of the adversary.
And that is the path that leads us to enjoy our privileges more and more. It is the path of safety that leads us to discern good and evil like day and night because the more we live up to our privileges, the more clearly we can tell good from evil, and the more dramatically we notice the loss of our privileges when we turn in a direction that is displeasing to that God that bestowed them upon us.