All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger. {C}{C}
This verse is similar to many other verses that enjoin the obedience of the Prophet coupled with the order to obey Allah Almighty or without it.
The benefit of the order to obey the commands of the Prophet his verdicts, and his judgment –even though this is part of the obedience to Allah – is to emphasize the obligation of following the Prophet and the obligation of obeying him, even if we do not find what he said precisely stated in the Book of Allah.
Shaykh Ibn Taymiyyah said:
"These texts mandate following the Prophet even if we do not find what he said explicitly stated in the Book (of Allah)." [End of quote]
Ibn Hazm explained this meaning further as he said:
"As for the repetition of the command of Allah to obey His Messenger after the command to obey Him, then it is so that ignorant people would not think that we are only obliged to abide by what Allah stated in the Quran, and that we are not obliged to obey His Messenger in regard to what he commanded us with what is not stated in the text of the Quran." [End of quote]
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Allah knows best.