Abinadi himself had predicted this inevitable outcome (Mosiah 13:3, 7–10). The official charge was probably blasphemy. It is couched in the terms that Abinadi insisted on: that Yahweh himself should come down among men. Noah and the priests must deny this assertion or admit that they had been teaching false doctrine. Ironically, Abinadi was sentenced to death on the very charge that he had leveled against Noah and his priests.
Why did Noah give Abinadi the chance to recant? Perhaps he was uneasy about the possibility that Abinadi, as a martyr, would become a rallying point for religious opposition to Noah. If Abinadi recanted, then the threat would be eliminated.