Tafsir of Al-Qamar 54:50

And Our commandment is but one as the twinkling of an eye. This is information about the execution of His will in His creation, just as He informed us the execution of His decree in them,

وما أمرنا إﻻ واحدة

(And Our commandment is but one). meaning, `We only command a thing once, without needing to repeat the command; and whatever We command comes to existence faster than the blinking of an eye without any delay, not even for an instant.' Allah said,