אור החיים — שמר ושמעת את כל הדברים האלה

Q — 'שמר ושמעת את כל הדברים' reverses the expected order — one normally hears a command first and then keeps it, so why 'keep' before 'hear'? And what is added by 'את כל'?

A — Or HaChaim explains that the verse commands two distinct things. 'שמר' (keep) refers to the Torah and mitzvot already known to Israel from Moshe — these one already possesses, so they are 'kept.' 'ושמעת' (and you shall heed) refers to the future enactments, the fences and safeguards (גדרים וסייגים) that the Sages will innovate — these one must accept as they arise. 'את כל' comes to include all the decrees, protections, and fences that the Sages will establish. The verse thus lays the foundation, near the entry to the Land, for the rabbinic expansion of Torah.