It will be recalled that when Laman and Lemuel were beating Nephi shortly after they lost the family fortune, Sam defended Nephi, so the older brothers beat on him, too. Then the angel appeared and chastised the older brothers. This leads us to assume that Sam was never rebellious like Laman and Lemuel but stood up for Nephi when he could. Notice that his blessing is combined with that of Nephi and his seed will be blessed right along with the seed of Nephi.