This verse officially introduces Jacob’s sermon. He describes his words as “teaching” the people, delivering his message at the temple, and doing so in response to Yahweh’s command. The setting and declaration tell us that this sermon is very important, sanctified by both location and heavenly declaration.
When Jacob indicates that he taught “in the temple” we should understand this phrase as it might have been used for the Jerusalem temple. There were places in the temple compound where one might teach and there were places where only the High Priest was allowed. Teaching “in” the temple would legitimately refer to anything inside the designated temple grounds. It would not suggest that the building housed a school or that it was large enough for a significant population to be under a single roof.