Abinadi continues his paraphrasing of Isaiah. The paraphrasing is the introduction to the conclusions that Abinadi wants to draw from Isaiah. He paraphrases to place his interpretation in line with Isaiah, who, as a brass plate prophet, must be accepted by the priests of Noah. What Abinadi must do is make it clear that Isaiah spoke of the same Son of God as did the Nephite prophets.
At this point Abinadi summarizes the trial and crucifixion of the Savior. The element of dying is included in Isaiah (see Isaiah 53: 8-9/Mosiah 14:8-9) but the very specific element of crucifixion depends upon Nephite prophets (we have it explicitly in 1 Ne. 1913, 2 Ne. 6:9, 10:3, 25:13 - sources that predate Abinadi and to which he must have had some access, even if only the idea as recorded on the large plates rather than the small).
A phrase that deserves some notice is "the will of the Son being swallowed up in the will of the Father." This is easy to see through our modern terminologies which separate the Father and the Son, thus the Son submitting to the Father would be natural. However, in Abinadi's usage the personage is the same, and the context is different. For Abinadi, this is a symbolic sense, where the flesh submits to the will of spirit.