For Nephi, mentioning Yahweh leads inevitably to the covenants between Yahweh and Israel (Nephi’s “fathers”). The law of Moses might be fulfilled in Christ, but the covenant with Abraham endures.
Redaction: The next transition is not as closely connected to the phrases immediately preceding them. The Abrahamic covenant is obvious, but the atonement (“eternal plan of deliverance from death”) is not. This theme, however, was so important in Jacob’s sermon that Nephi apparently wrote this passage immediately after writing Jacob’s sermon or after rereading it. Therefore, this verse comes from the connection Nephi makes between his testimony of the Atoning Messiah, Jacob’s testimony, and his recent recording of Jacob’s sermon on the subject.