Nephi anticipated that many of his readers would not understand the meaning of speaking with the tongue of angels (v. 2), so he further explained what it means. Since Christ and the Holy Ghost are one in doctrine, and angels speak by the power of the Holy Ghost, they teach the words that Christ would speak (v. 3). Therefore, the formula given by Nephi to speak these same words is to feast upon Christ’s words. A feast, especially in the Jewish culture from where Nephi came, is when you eat for hours partaking of all of the delicious foods that are before you. The symbolism of feasting on Christ’s words is to study widely, for long hours that you may understand the doctrine of Christ. Through studying the words of Christ it will tell you, by study, how you should live.
Nephi adds a disclaimer to his formula. If we do not ask (prayer) and knock (try to live as the words of Christ tell you), we will not come into the light of what we must do, but will perish in the darkness of the world (v. 4). He then adds the comment that the Holy Ghost will show us what we should do. There is a difference in the Holy Ghost showing us, and the words of Christ telling us what to do. As stated above, study will give us spiritual knowledge. The Holy Ghost will bring us personal revelation. This is learning by faith. We need both sources in our lives to follow the path to eternal life. The Lord has instructed us to “seek learning, even by study and also by faith” (D&C 88:118).
Those who followed Nephi’s formula had sufficient to lead them on the path to eternal life until the time of Christ’s coming in the flesh. After Christ had fulfilled the law of Moses, further instructions would be given (v. 6).