After reiterating the nature of the great gift of complete liberty and eternal life given by the great Mediator, Lehi pled with his sons to accept the atoning work of that Mediator-Messiah. A mediator is one who intercedes on behalf of another, who pleads for another, and who reconciles persons or parties who are at odds or estranged from each other. The scriptures mention two principal mediators who devoted their lives to reconciling the children of God with their God. The first, chronologically speaking, was a type and foreshadow of the second. The first interceded on behalf of the children of Israel. The second interceded on behalf of all humankind. The first was the mediator of a lesser law and covenant. The second was the mediator of an eternal law and covenant. The first was mortal and temporary. The second was God, infinite and eternal. The first was Moses. The second was Jesus Christ—the great Mediator, as Lehi declared.
Of these two mediators Paul wrote (sounding much like Lehi): “Wherefore then, the law was added because of transgressions, till the seed should come to whom the promise was made in the law given to Moses, who was ordained by the hand of angels to be a mediator of this first covenant, (the law).
“Now this mediator was not a mediator of the new covenant; but there is one mediator of the new covenant, who is Christ, as it is written in the law concerning the promises made to Abraham and his seed. Now Christ is the mediator of life; for this is the promise which God made unto Abraham” (JST, Galatians 3:19–20).
The Old Testament contains illustrations of Moses interceding on behalf of the children of Israel. But these pale in comparison to the deeds of Jesus Christ, the Holy Messiah, who came to earth to “make intercession for all the children of men,” who was “the mediator of the new covenant, who wrought out this perfect atonement through the shedding of his own blood” (D&C 76:69). That is why the apostle Paul referred to Christ as the “one mediator between God and men” (1 Timothy 2:5). The old law and covenant administered under Moses “made nothing perfect, but was only the bringing in of a better hope” (JST, Hebrews 7:19), by which hope, that is, the new covenant or gospel of Jesus Christ, we are “made perfect” (D&C 76:69). Therefore, father Lehi earnestly encouraged his sons (and every individual really) “to choose liberty and eternal life, through the great Mediator of all men.” Said he, “Look to the great Mediator, and hearken unto his great commandments; and be faithful unto his words, and choose eternal life.”
It is only through the atonement of Jesus Christ that human beings can inherit eternal life. The Atonement is the very essence, the core, of Jesus’ mediation and intercession (D&C 45:3–5). Lehi knew that if his sons did not choose the way of eternal life, they would, by default, choose “eternal death” and become captive to the devil, who will “reign over you.”