Ibn Ezra on Genesis 2:16/אבן עזרא על בראשית ב׳:ט״ז

1AND THE LORD GOD COMMANDED THE MAN. The verb tzivvah (command) with the preposition al (upon) implies a prohibition. We similarly read, I will also command (atzavveh) the clouds (al he-avim) That they rain no rain upon it (Is. 5:6).