Benjamin expands on his reference to his father, Mosiah1’s, discourse. He had referenced his father speaking of those who follow the evil spirit. The last phrase of the previous verse (33) noted that those who followed the evil spirit contradicted what they knew to be true. In these verses, Benjamin brings that speech forward in time to apply it to his current audience.
When he says, “there are not any among you, except it be your little children that have not been taught concerning these things,” he picks up on the idea that those who would follow the evil spirit go against those teachings. This people have been taught from true sources, from the prophets recorded on the plates of brass and all of the righteous Nephite fathers until the current time. Benjamin testifies that these are true teachings.
They have listened to those true teachings, and they should continue to listen to the good spirit and true teachings. They should beware of the contentions that recently led so many away.