Jamieson, Fausset and Brown on Ezekiel 4:14

14. Ezekiel, as a priest, had been accustomed to the strictest abstinence from everything legally impure. Peter felt the same scruple at a similar command (Ac 10:14; compare Is 65:4). Positive precepts, being dependent on a particular command can be set aside at the will of the divine ruler; but moral precepts are everlasting in their obligation because God cannot be inconsistent with His unchanging moral nature.

abominable flesh--literally, "flesh that stank from putridity." Flesh of animals three days killed was prohibited (Le 7:17, 18; 19:6, 7).