Sforno on Deuteronomy 27:9/ספורנו על דברים כ״ז:ט׳

1וידבר משה והכהנים הלוים, Moses co-opted the priests to caution them on the importance of studying the Torah in depth. This was because it was their primary duty to teach the Torah to the people. [service in the Temple occupied only a few days’ a year of each priest’s time. Ed.] (compare Deut. 33,10 יורו משפטיך ליעקב, “they shall teach Your laws to Yaakov.”)

2הסכת, illustrate the concepts for you in your mind, as in Amos 5,26 את סכות מלככם, “they even named the idol ‘image’.”