רמב"ן — ויעש אהרן ובניו את כל הדברים אשר צוה ה' ביד משה

Q — The closing pasuk of Tzav reports compliance with an unusual phrasing: 'ויעש אהרן ובניו את כל הדברים אשר צוה ה' ביד משה.' The standard formula in such reports is 'כאשר צוה ה' את משה' (e.g. Mishkan-completion). Why the change here?

A — Ramban: the change is a quiet foreshadow of the Nadav-Avihu tragedy in the next parsha. The Torah does not say 'they did as Hashem commanded Moshe' — only that 'they did all the things Hashem commanded.' That technically-true phrasing leaves room for what happened in the next chapter: Aharon's sons did all that was commanded — and added on their own initiative 'אש זרה אשר לא צוה אותם.' The closing pasuk is a literary fissure, prefiguring what comes. The chiddush is a sensitivity to ominous silences in Tanach's compliance formulas.