D&C 121: 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.
I never got a good answer to my question. But I do understand it now without any question. The point is that if we are doing as we ought we will find ourselves connected to the powers of heaven. And if we are not finding ourselves more and more connected with the powers of heaven it is because we are not living the principles of righteousness.
The lesson is that if we are genuinely living righteously we will find ourselves gradually enjoying the Holy Ghost more powerfully over the years. We will find that we either learn the gospel by the Holy Ghost or not at all, and that he truly is a revelator. We will discover for ourselves that God stands revealed, or remains forever unknown.
If we don't find, in time, that the gospel is connecting us to the powers of heaven, then we need to rethink whether we are living principles of righteousness. We need to question our indulgences that we think the Lord excuses (media seems to be an enormous one these days) and we need to engage more genuinely in saving the souls of man.
If we are growing into the Holy Ghost, then if we press forward diligently we will find ourselves in time enjoying the rights and priveleges of the priesthood.
D&C 107:18 The power and authority of the higher, or Melchizedek Priesthood, is to hold the keys of all the spiritual blessings of the church—
19 To have the privilege of receiving the mysteries of the kingdom of heaven, to have the heavens opened unto them, to commune with the general assembly and church of the Firstborn, and to enjoy the communion and presence of God the Father, and Jesus the mediator of the new covenant.
Now I have a long way to go. But I do understand what the one lesson is.
It is the lesson that apostate Christianity could not learn. It is the lesson that they do not find themselves connected to the powers of heaven in this life precisely because they will not live the required principles of righteousness. It is the lesson that when we really live principles of righteousness as we should, when we really believe as we ought, we will find, as Christ promised, that these signs follow them that believe. It is the lesson that when we are converted in the sense Christ wanted of Peter, we will do the works of Peter, and when we have the faith the Christ wanted of his disciples, then we will do the works of his disciples. It is the lesson that
D&C 130:20 There is a law, irrevocably decreed in heaven before the foundations of this world, upon which all blessings are predicated—
21 And when we obtain any blessing from God, it is by obedience to that law upon which it is predicated.
and that if we are not, in time, finding ourselves connected to the powers of heaven it is because we are not growing into the principles of righteousness as God measure them.
We must strive to live righteously enough here to find ourselves becoming connected to the powers of heaven in time. If the Holy Ghost is a stranger to us here, he will be a stranger to us hereafter. If we are not connected to the powers of heaven here, we will not find ourselves connected to them hereafter. And then how can they save us? For it is by the powers of heaven being exercised in our behalf that we have our only hope of salvation and exaltation in the life to come.