As the three brothers stayed outside the walls, Nephi crept alone into the city, at night, going back towards the house of Laban (4:5). Perhaps Moses was again on Nephi’s mind and should be on the reader’s mind here, not only in Nephi’s immediate outburst of confidence as the armies of Pharaoh had been justifiably killed in the Sea, but also as Moses himself had not been punished for earlier having killed a brutal Egyptian overlord (Exodus 2:12). By mentioning Moses, Nephi’s story is already hinting that someone might likewise justifiably die in the unfolding of Nephi’s account.
If a death somehow would occur in Nephi’s attempt to get the plates, one of the main legal issues that would have arisen would concern the state of his mind as he slew Laban. Anticipating that issue, Nephi expressly affirmed that he was "led by the spirit, not knowing beforehand the things which [he] should do" (4:6). Almost as Moses led the children of Israel through the wilderness by the pillar of fire at night, Nephi becomes an embodiment of the children of Israel as they too had faced mortal dangers themselves. Nephi’s testimony that he was led solely by the spirit of God substantiates a lack of pre-planning, pre-meditation, lying in wait, coming presumptuously, or desiring revenge, or any wish to harm Laban. He had not schemed to find Laban by guile or by positioning himself somewhere around Laban’s house hoping to be able to ambush him.
Apparently being completely unarmed, Nephi had hoped somehow to gain access to Laban’s treasury and to persuade someone who controlled access to the plates to cooperate with him. But how on earth this was going to happen was still a total mystery to him. When he sat down much later to write his story, Nephi began by saying, "I’ve been taught by my father. I know of the mysteries of God, nevertheless I have suffered a lot of afflictions in my day" (1 Nephi 1:1). What happened there in the dark corners of Jerusalem that night may well have been one of those mysteries that Nephi must have looked back on and asked himself, how on earth did all that happen?
I think it’s really important that Nephi went alone for two reasons. One is, strategically, they didn’t want to enter the city like a gang of robbers and have whatever could happen under those circumstances, and if they went in as a group that was a real possibility. Secondly, I think for the purpose of faith and for the legal thing, it wasn’t a mob that set about Laban; it wasn’t a group of four. It was one person alone. The Lord delivered Laban into Nephi’s hand.
As Nephi approached the house of Laban, the narrative tells, he "beheld a man," that "he had fallen to the earth" right on Nephi’s path, and that he was "drunken with wine," and finally that Nephi "came to him." It seems that Nephi was still just wondering what he might learn or perhaps even how he might help this fallen person. But he only then discovered "that it was Laban" (4:7–8). No one could have been more surprised than Nephi.
Nephi immediately noticed Laban’s personal sword and took it out of its sheath, admired its hilt of pure gold and its blade of precious steel. He may have seen this sword before, but probably had never held it. Considerable irony looms in the fact that Laban would be killed not only by his own sword, after having threatened to kill Nephi and his brothers, but also in the fact that the sword was extremely valuable. The instrument of Laban’s death represents Laban’s lust for gold and precious things, which was a cause of his own undoing.
At this point, Nephi reports that he "was constrained by the spirit that [he] should kill Laban" (4:10). Nevertheless, he resisted and reflected: "Never at any time have I shed the blood of man. And I shrunk and would that I might not slay him" (4:10). With these words, Nephi certifies that he was "constrained" by some urge (4:10) to do this deed. He was constrained. It was not of his own planning or volition. For several wise reasons, his preferences surely would have been to somehow take advantage of the situation he had stumbled into but without having to kill Laban. Nephi was inexperienced, not bloodthirsty. Nephi’s statements take his ensuing actions out of the legal domain of culpable voluntary homicides.
Hearing words quoted to him from Exodus 21:13, saying, "Slay him, for ‘the Lord hath delivered him into thy hands’" (4:11), Nephi paused and reflected further. He debated with himself on three grounds, but none of these reasons were persuasive: (1) Laban had sought to take away Nephi’s own life (and the life of his brothers)—but that attempt by Laban was unsuccessful and thus was not legally culpable; (2) Laban would not obey the commandment of God—but Laban had no obligation to consider a demand made by Lehi’s sons as tantamount to a divine command; and (3) Laban had taken away their property—but stealing property was not a crime worthy of capital punishment. Although Nephi’s situation—being alone, unarmed, and out of options—was different from David’s situation as David and his soldier Abishai deliberated and decided not to kill Saul, Nephi and David both agonized over the seriousness of taking such an irreversible action.
To make it unmistakably clear that only one other reason ultimately justified Nephi’s action, Nephi then tells that the Spirit repeated the injunction a second time, quoting again from Exodus 21, "Slay him, for the Lord hath delivered him into thy hands" (4:12). These words of the Spirit certify that the Lord had brought together the facts and circumstances, together with the means and methods, necessary for Nephi to slay Laban, and thus it was not so much Nephi, but "the Lord, [who] slayeth the wicked to bring forth his righteous purposes" (4:13). This motivation was similar to that of divine intervention in military combat. Laban, after all, was carrying weapons of war and was wearing armor.
And finally, the word of the Lord explained: "It is better that one man should perish than a nation should dwindle and perish in unbelief" (4:13). This expression resonates with another rule of biblical law found in the story of Sheba, a rebel who was guilty of treason against David (2 Samuel 20). When Sheba ran to the city of Abel seeking protection, one of David’s commanders named Joab demanded that Sheba be released to him, otherwise Joab would kill everyone in the city. When the people of Abel beheaded Sheba, they set an important legal precedent. It was subsequently invoked over the years under Jewish law to justify, under certain rare circumstances, the killing of one person in order to preserve an entire innocent group. This has been called "the one for many" principle. This rationale was reputedly involved again, when King Jehoiakim was turned over to the Babylonians in order to prevent the city of Jerusalem from being punished (2 Chron. 36:6). Jehoiakim was then, presumably, to be executed by the Babylonians, and that had happened only a few months before the point at which the account in 1 Nephi begins.
Hearing that twice-repeated command and legal justification from the Spirit of the Lord, Nephi cut off Laban’s head. He took him "by the hair of the head" (4:18), as Judith reportedly also did. She cut off the head of Holofernes, whose armies had surrounded Jerusalem. No one witnessed either of these beheadings. Like Phinehas in Numbers 25, Nephi and Judith are portrayed as righteously and justifiably taking the law into their own hands, acting under extreme circumstances solely for the benefit of their entire people.