Avos 1:16

Rabban Gamliel said to get yourself a teacher in order to remove yourself from situations of doubt, and not to make a practice of separating tithes by estimating.

Avos 1:17

Rabban Gamliel’s son Shimon said, “My whole life I grew up among the Sages and I found nothing better for a person than silence. Expounding on the Torah is not the most important thing, practicing it is. And whoever talks too much causes sin.”