Isaiah opened the door for Abinadi to discuss the atoning mission of the Messiah when he said that our iniquities would be placed upon the suffering servant. Abinadi makes that more explicit by recounting the doctrine of the Messiah as it had been taught among the Nephites from Nephi’s time. Jehovah himself would come down and do two very important things. He would first break the bands of death. Then He would mercifully break the bands of sin.
However, Abinadi is indirectly speaking about the passage that the priests presented him with. In Mosiah 12:23 we have the quotation of the line “he hath redeemed Jerusalem,” from Isaiah 52:9. In verse 9 above, Abinadi declares that when Jehovah takes upon himself our sins, He redeems us.
Abinadi weaves in a line from Isaiah 53:8 (quoted in Mosiah 14:8) which asks “who shall declare his generation?” In Isaiah 53:8 the rest of the verse speaks of His death, thus leaving Him without seed. Thus, Abinadi plays off the idea of the Messiah not having subsequent offspring or generation, and suggests that He indeed will see His seed. Then Abinadi asks who that seed might be, leading to his next point.