Yahweh-Messiah tells the people that all who have received him have “become” the sons of God. The past tense points to a promise fulfilled for Old World believers but also to the foundational covenant from Benjamin’s time:
And we are willing to enter into a covenant with our God to do his will, and to be obedient to his commandments in all things that he shall command us, all the remainder of our days, that we may not bring upon ourselves a never-ending torment, as has been spoken by the angel, that we may not drink out of the cup of the wrath of God.
And now, these are the words which king Benjamin desired of them; and therefore he said unto them: Ye have spoken the words that I desired; and the covenant which ye have made is a righteous covenant.
And now, because of the covenant which ye have made ye shall be called the children of Christ, his sons, and his daughters; for behold, this day he hath spiritually begotten you; for ye say that your hearts are changed through faith on his name; therefore, ye are born of him and have become his sons and his daughters. (Mosiah 5:5–7)
The Nephite gospel was embodied in this covenant. While the covenant originally signified an entire people, it was preserved in the church and was renewed in the baptismal covenant.