2 Nephi 9:8-9:
For behold, if the flesh should rise no more our spirits must become subject to that angel who fell from before the presence of the Eternal God, and became the devil, to rise no more. And our spirits must have become like unto him, and we become devils, angels to a devil, to be shut out from the presence of our God, and to remain with the father of lies, in misery, like unto himself
Compare with 2 Nephi 2, verses 17
And I, Lehi, according to the things which I have read, must needs suppose that an angel of God, according to that which is written, had fallen from heaven; wherefore, he became a devil
and 27
the captivity and power of the devil; for he seeketh that all men might be miserable like unto himself.
Jacob's speech continues in 2 Nephi 10. In verses 23-24:
Therefore, cheer up your hearts, and remember that ye are free to act for yourselves—to choose the way of everlasting death or the way of eternal life. Wherefore, my beloved brethren, reconcile yourselves to the will of God, and not to the will of the devil and the flesh
Compare with 2 Nephi 2:26-29
to act for themselves… Wherefore, men are free according to the flesh… And now, my sons, I would that ye…choose eternal life, according to the will of his Holy Spirit; And not choose eternal death, according to the will of the flesh and the evil which is therein
As we know, 2 Nephi 2 contains Lehi's words to Jacob. It seems that he has remembered the words of his father and perhaps also studied the same passage on the brass plates that Lehi refered to in verse 17. Now, a few decades later, it is Jacob's turn to teach these things to his people that he learned from his father in his youth.