2 Nephi 10 and 11 - Nephi delights in showing Christ will come

Nephi purposefully chose to use Jacob's words to teach about Christ because Jacob was an eyewitness of Christ. So was Isaiah; Nephi talks about the need to use witnesses to prove things and that God has done that abundantly regarding Christ.

Here's verses explaining Nephi's thinking:

2 And now I, Nephi, write ^amore of the words of ^bIsaiah, for my soul delighteth in his words. For I will liken his words unto my people, and I will send them forth unto all my children, for he verily ^csaw my ^dRedeemer, even as I have seen him.

3 And my brother, Jacob, also has ^aseen him as I have seen him; wherefore, I will send their words forth unto my children to prove unto them that my words are true. Wherefore, by the words of^bthree, God hath said, I will establish my word. Nevertheless, God sendeth more ^cwitnesses, and he proveth all his words.

Also, I think Jacob's conclusion to his 4 chapters on Isaiah is great - reconcile your actions with the way God wants you to live (as it brings happiness, joy, etc.), but then it's only through Christ's grace that you're saved:

23 Therefore, ^acheer up your hearts, and remember that ye are^bfree to ^cact for yourselves—to ^dchoose the way of everlasting death or the way of eternal life.

24 Wherefore, my beloved brethren, ^areconcile yourselves to the^bwill of God, and not to the will of the devil and the flesh; and remember, after ye are reconciled unto God, that it is only in and through the ^cgrace of God that ye are ^dsaved.

Great verse, similar to 2 Nephi 26:25 that talks about grace being the way we're saved.