Alma's sons demonstrate the importance of setting a good example. Even more so, they demonstrate the damage that can be cause by a bad example. Shiblon and Helaman had been good examples for their little brother, but Corianton had not. Unfortunately, Corianton's bad example had more of an effect on the Zoramites than the good examples of Shiblon, Helaman, Alma, and Amulek put together. Even Alma's credibility was destroyed by Corianton, for when they saw your conduct they would not believe in my words (v. 11).
Harold B. Lee
"A good example is powerful. Our task is to 'hold up' to the world that which Jesus has done for man: the Atonement, the example He set, and the teachings He has given us personally and through His prophets, ancient and modern. The Master also counseled us: 'Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven' (Matthew 5:16). This was not urging us to be immodest or ostentatious, since Jesus also warned us not to do good things 'to be seen of [men]' (Matthew 6:1-2). Yet, as Harry Emerson Fosdick observed, we should 'let the finest things that God has wrought in us' shine forth, so that we are not guilty of either of the two basic forms of hypocrisy: pretending to be better than we are, or letting ourselves appear worse than we are." (Teachings of Harold B. Lee, p. 508)
Elder Francis M. Lyman
"It is our duty to preach the Gospel. That is our chief calling--to preach the Gospel by word, to preach it by our conduct throughout our lives. Nothing is stronger, nothing is more real, or more reliable and substantial than the good example that men set in their lives." (Conference Reports, Apr. 1910, p. 31)
Elder Abraham O. Woodruff
"We expect that every officer in this Church will set a good example, and say to the people, Follow me; that he will not require anything of his people that he is not willing to do himself. We expect this to be the case in every organization of the Church, among the sisters as well as the brethren." (Conference Reports, Apr. 1901, p. 14)