Mosiah 17:6 - 17:10

Mosiah 17:6 And after three days, having counseled with his priests, he caused that he should again be brought before him.

For the next three days they debated what to do with him and what they might charge him with that would justify the death penalty.

Mosiah 17:7 And he said unto him: Abinadi, we have found an accusation against thee, and thou art worthy of death.

He was then brought again before the king and the charges made.

Mosiah 17:8 For thou hast said that God himself should come down among the children of men; and now, for this cause thou shalt be put to death unless thou wilt recall all the words which thou hast spoken evil concerning me and my people.

They accused him of saying the it would be God himself that would be born as a mortal. This preachings this doctrine was apparently against the law. They said that it would stir up the people and cause civil unrest and that was punishable by death. So they gave Abinadi a chance to recant or he would be executed.

Mosiah 17:9 Now Abinadi said unto him: I say unto you, I will not recall the words which I have spoken unto you concerning this people, for they are true; and that ye may know of their surety I have suffered myself that I have fallen into your hands.

Abinadi refuses to back down. And says that he backs up his conviction by allowing himself to become their prisoner.
[He had been living outside the city and could have done so for the rest of his life, but since he allow himself to be captured and he knew he would, it was proof of his sincerity.]

Mosiah 17:10 Yea, and I will suffer even until death, and I will not recall my words, and they shall stand as a testimony against you. And if ye slay me ye will shed innocent blood, and this shall also stand as a testimony against you at the last day.

Abinadi says he will suffer death as proof of the truthfulness of what he is saying. And if he is executed, they will have killed an innocent man and will have to account for it at judgment day.