“Salvation is nothing more nor less than to triumph over all our enemies and put them under our feet. And when we have power to put all enemies under our feet in this world, and a knowledge to triumph over all evil spirits in the world to come, then we are saved, as in the case of Jesus, who was to reign until He had put all enemies under His feet, and the last enemy was death [see 1 Corinthians 15:25–26]. (TJS, The Great Plan of Salvation, Chapter 17)There is a lot here. Salvation is to triumph over all our enemies. The last enemy we must overcome is death. However we cannot overcome all things in this life, only by grace to grace, exaltation to exaltation, line upon line. That is a blessing to celestial beings beyond the grave though, "And they shall overcome all things." (D&C 76:60).
Thus the atonement allows us to rely upon His power until we learn for ourselves to "overcome all things" death being the last enemy of all.
Not only are we to put all enemies under our feet in this world but it is required to do so. Why? For the purpose of gaining the knowledge to triumph over all evil spirits in the world to come. THEN are we saved. The lectures on faith states
Where shall we find a saved being? for if we can find a saved being, we may ascertain, without much difficulty, what all others must be, in order to be saved - they must be like that individual or they cannot be saved: we think, that it will not be a matter of dispute, that two beings, who are unlike each other, cannot both be saved; for whatever constitutes the salvation of one, will constitute the salvation of every creature which will be saved: and if we find one saved being in all existence, we may see what all others must be, or else not be saved. We ask, then, where is the prototype? or where is the saved being? We conclude as to the answer of this question there will be no dispute among those who believe the bible, that it is Christ: all will agree in this that he is the prototype or standard of salvation, or in other words, that he is a saved being. And if we should continue our interogation, and ask how it is that he is saved, the answer would be, because he is a just and holy being; and if he were any thing different from what he is he would not be saved; for his salvation depends on his being precisely what he is and nothing else; for if it were possible for him to change in the least degree, so sure he would fail of salvation and lose all his dominion, power, authority and glory, which constitutes salvation; for salvation consists in the glory, authority, majesty, power and dominion which Jehovah possesses, and in nothing else; and no being can possess it but himself or one like him: (Lecture 7)TWO beings unlike each other cannot both be saved. Christ is the prototype. And how did Christ gain the knowledge to triumph over all his enemies or should I say when did he have the knowledge to overcome all things?
Isaiah gave us a power imagery of the suffering of Christ and His atonement.
10 ¶Yet it pleased the Lord to bruise him; he hath put him to grief: when thou shalt make his soul an offering for sin, he shall see his seed, he shall prolong his days, and the pleasure of the Lord shall prosper in his hand.His suffering in Gethsemane. His atonement! It was through that travail of his soul that he was able to "by his knowledge" experience what each mortal could, can, or would face. It was there he knew what each of us would need to overcome the obstacle of sin placed before. Thus he could now "by his knowledge" which he learned and overcoming eventual death on the cross, succor all of us "by his knowledge." Because He gained the required knowledge, thus He knows what YOU need at any given moment to overcome, fix, repair what is broken, remove any discouragement, or burden placed upon you. The atonement can cleanse you every whit but it is up to you to rise up and accept the burden placed before you. Whatever that is, He can bestow the required knowledge along with the comfort you need to endure it well.
11 He shall see of the travail of his soul, and shall be satisfied: by his knowledge shall my righteous servant justify many; for he shall bear their iniquities.
Lets go back to the original quote.
“Salvation is nothing more nor less than to triumph over all our enemies and put them under our feet. And when we have power to put all enemies under our feet in this world, and a knowledge to triumph over all evil spirits in the world to come, then we are saved, as in the case of Jesus, who was to reign until He had put all enemies under His feet, and the last enemy was death [see 1 Corinthians 15:25–26]. (TJS, The Great Plan of Salvation, Chapter 17)Triumphing over our enemies here bestows knowledge on the other side or the "world to come" for "No person can have this salvation except through a tabernacle." (ibid) And Christ, being the prototype, suffered and was able to "by his knowledge" justify and sanctify many.
After we can triumph over all evil spirits in the world to come, then we are saved. Thus Joseph said,
“… A man is saved no faster than he gets knowledge, for if he does not get knowledge, he will be brought into captivity by some evil power in the other world, as evil spirits will have more knowledge, and consequently more power than many men who are on the earth. Hence it needs revelation to assist us, and give us knowledge of the things of God.”15 (TJS, Ch 22)And so the promise is to all who rise up here and now. And how do you rise up? How does one become at the level of Celestial? By ones knowledge. You cannot be saved in ignorance. And when you get knowledge sufficient to lay hold upon Eternal life, for the difference between an saved being and one that is not is the degree of their faith (See Lectures on Faith), you can also be in a position to overcome all things. As similar language puts it "ask to know the mysteries" for D&C 19:8 shows the importance, "I will explain unto you this mystery, for it is meet unto you to know even as mine apostles." The Lords servants knows the mysteries of God.