These verses are Lehi’s explanation of salvation as a free gift. In their fallen state, men are given the law and are instructed sufficiently to know good from evil (v. 5). Law is the basic condition of agency. Everyone is born with the Spirit of Christ innately within him, and it “is given to every man, that he may know good from evil” (Moroni 7:16).
The second condition of agency is that man must be able to understand the law. The Lord revealed to this dispensation that the children are not received into the Church “unless [they] have arrived unto the years of accountability before God, and (are) capable of repentance” (D&C 20:71). The Lord also revealed that parents were responsible to teach the basic principles to their children before they become “eight years old” when “their children shall be baptized” (D&C 68:25–26). Older people “that hath no understanding (handicapped mentally)” are in the same category (D&C 29:50).
“By the law no flesh is justified” (v. 5) is saying what Paul said to the Romans; “For all have sinned, and come short of the glory of God” (3:23). Lehi says that “by the temporal law they were cut off” (v. 5). Alma later explained: “Now we see that Adam did fall by the partaking of the forbidden fruit, according to the word of God; and thus we see, that by his fall, all mankind became a lost and fallen people… . And we see that death comes upon mankind, yea, the death which has been spoken of by Amulek, which is the temporal death” (Alma 12:22, 24). Eating of the fruit violated a law. “But of the tree of the knowledge of good and evil, thou shalt not eat of it, nevertheless, thou mayest choose for thyself, for it is given unto thee; but, remember that I forbid it, for in the day thou eatest thereof thou shalt surely die” (Moses 3:17; see also Genesis 2:17). The fruit apparently caused a temporal change, making Adam and Eve mortals and subject to death. Lehi states further; “by the spiritual law they perish from that which is good, and become miserable forever” (v. 5). They were cast out of the garden of Eden, and spiritually alienated from God. Alma also explained: “Therefore, as the soul could never die, and the Fall had brought upon all mankind a spiritual death as well as a temporal, that is, they were cut off from the presence of the Lord, it was expedient that mankind should be reclaimed from this spiritual death” (Alma 42:9). Being reclaimed from spiritual (and temporal) death would negate their misery forever.
According to Lehi: “redemption cometh in and through the Holy Messiah; for he is full of grace and truth” (v. 6). Salvation was in Christ, not in keeping the law. “There [was] a law given, and a punishment affixed” for the law being broken “justice claimeth the creature” (Alma 42:22). Since all have sinned, or broken the law, Christ offered his soul as a sacrifice for sin (v. 7) in the garden of Gethsemane, “and satisfied the demands of justice (the law)” (Mosiah 15:9). Therefore by his grace came the redemption. “He that keepeth his commandments receiveth truth and light, until he is glorified in truth and knoweth all truth” (D&C 93:28). Christ is “the Spirit of truth … And no man receiveth a fullness (of truth) unless he keepeth his commandments” (D&C 93:26–27). We progress towards eternal life as we receive truth, therefore by his truth cometh redemption. However, there is a condition placed upon the ends of the law being answered (paid). Only those who have a broken heart, realize that they caused Christ to suffer for them and are sorrowful (repentant) for doing so. They have a contrite spirit, when they are willing to be taught the truth, to and accept the truth and will have the law answered for them by Christ (v. 7).
“How great the importance to make [the plan of salvation] known unto the inhabitants of the earth, … there is no flesh that can dwell in the presence of God, save it be through the merits, and mercy, and grace of the Holy Messiah” (v. 8). Christ laid down his life and took it up as the first to rise from the dead. Thus, he brought about the resurrection to overcome the temporal law that was broken, whereby man became fallen and mortal and thus would suffer physical death (v. 8). He made intercession for all mankind to overcome the effects of the Fall if they believed in him (v. 9).