When Nephi uses the words "I know," he might be conveying more than simple faith or a positive attitude. He might be conveying a more sure knowledge of a covenant relationship with the Lord which he had previously alluded to in 1 Nephi 2. In that brief mention, notice that:
(1) Nephi "was exceedingly young yet large in stature" (implying spiritual maturity more than physical)
(2) he had "great desires to know of the mysteries of God, wherefore he did cry unto the Lord,"
(3) "he [the Lord] did visit me," and
(4) "I did not rebel" (1 Nephi 2:16, emphasis added)
For the Lord's part, he blesses Nephi according to his obedience to the covenant: "And inasmuch as ye shall keep my commandments, ye shall prosper, and shall be led to a land of promise; yea, even a land which I have prepared for you; yea, a land which is choice above all other lands." . . . "And inasmuch as thou shalt keep my commandments, thou shalt be made a ruler and a teacher over thy brethren." (1 Nephi 2:20. 22) Note should be taken of the specific covenant words and phrases here. [Alan C. Miner, Personal Notes] [See the commentary on 1 Nephi 5:2, 5:5; 2 Nephi 33:4; Alma 34:8; 3 Nephi 14:23]