We are all familiar with the scripture:
D&C 121:33 How long can rolling waters remain impure? What power shall stay the heavens? As well might man stretch forth his puny arm to stop the Missouri river in its decreed course, or to turn it up stream, as to hinder the Almighty from pouring down knowledge from heaven upon the heads of the Latter-day Saints.
34 Behold, there are many called, but few are chosen. And why are they not chosen?
35 Because their hearts are set so much upon the things of this world, and aspire to the honors of men, that they do not learn this one lesson—
36 That the rights of the priesthood are inseparably connected with the powers of heaven, and that the powers of heaven cannot be controlled nor handled only upon the principles of righteousness.
We usually leave off verse 33 when quoting this, but it is part of the context. The subject is revelation. In verse 33 we learn that man cannot stop God from pouring revelation down upon the heads of the Latter-day Saints. But in verse 35-36 we learn that the Saints themselves can stop him from doing so by failing to live by God's principles of righteousness. The point is that the rights of the priesthood, the right to be connected with the powers of heaven, can only by controlled and handled by the principles of righteousness.
Contrast this with what God stated about the apostate churches of Joseph Smith's day.
Joseph Smith History 1:19 I was answered that I must join none of them, for they were all wrong; and the Personage who addressed me said that all their creeds were an abomination in his sight; that those professors were all corrupt; that: “they draw near to me with their lips, but their hearts are far from me, they teach for doctrines the commandments of men, having a form of godliness, but they deny the power thereof.”
There we have the words of Jesus Christ on the religions of Joseph's day. The point being made is that they "teach for doctrines the commandments of men" rather than insisting on God's own principles of righteousness. Consequently, they had no power to connect a man to the powers of heaven. Hence, while they had a form of godliness in their teachings, they denied the power thereof. They denied that man even could be connected to heaven because they knew from their own experience that their teachings had no power to do so.
They, like the members that D&C 121 warns, did not learn this one lesson - that the rights of the priesthood are inseparably connected with the powers of heaven, and that the powers of heaven cannot be controlled nor handled only upon the principles of righteousness.