In 8:36 it tells us that Aharon and his sons did as Hashem commanded through Moshe.
Rashi tells us that this tells us the praise of Aharon and sons that they did not divert at all from what Hashem told them to do. Everything was followed precisely.
Why does the Torah have to keep telling us this? This is exactly why they were the leaders rather than other people leading the nation - because they followed Hashem's instructions precisely without mixing in their own preferences.
The Torah keeps telling us how they followed precisely what Hashem said. Ok, we got the point already. Why keep telling us?