Alma gives us a great example in this verse. He is teaching a principle he is not sure about. Yet, he doesn’t teach it as doctrine but as his opinion. It turns out, of course, that his opinion was exactly correct—that the righteous were resurrected at the time of Christ’s resurrection. But this phrase, “I give it as my opinion,” should be the motto of every gospel doctrine teacher and Priesthood instructor who is teaching something which is not in the scriptures. The fact that this phrase is used only once in the Book of Mormon is a lesson to all of us. We should never teach as doctrine those things which we cannot support with the scriptures and the words of the Brethren.