The Importance of Singling Out Allah in All Forms of Worship
ALLĀH says,
فَلَا تَجۡعَلُواْ لِلَّهِ أَندَادًا
Then do not set up rivals unto ALLĀH ˹in worship˺
That is, equals from among HIS creation which you worship as you should worship ALLĀH and love as you should love ALLĀH, although they are created beings like you who receive provision and are under HIS control, having not the slightest power either in heaven or on earth, and they cannot benefit or harm you at all.
وَأَنتُمۡ تَعۡلَمُونَ
while you know ˹that HE Alone has the right to be worshipped˺.
That is, when you know that ALLĀH has no partner or equal with regard to the power of creation, granting of provision or control of the universe, and HE has no partner in worship. So how can you worship other gods besides HIM when you know these things? This is something that is very strange and extremely foolish.
This verse combines the command to worship ALLĀH alone and the prohibition on worshipping anything other than HIM. It offers clear evidence that it is obligatory to worship HIM and that the worship of anything other than HIM is invalid. This refers to tawheed ar-ruboobiyah (oneness of the divine Lordship), which implies that HE is the only One Who creates, grants provision and controls. If anyone accepts that HE has no partner in these things, then by the same token he should also accept that ALLĀH has no partner in worship. This is the clearest rational evidence for the oneness of the Creator and the invalidity of associating partners with HIM.
{Tafsir As-Sa’di}
Abdullāh ibn Mas’ud (may ALLĀH be pleased with him) reported: I said, “O Messenger of ALLĀH, what is the greatest sin?”
The Prophet (ﷺ) said: “To set up a partner alongside ALLĀH, even though HE alone created you.”
{Al-Bukhārī #6001, Muslim #86}
Ibn Abbas (may ALLĀH be pleased with them) reported: A man said to the Prophet (ﷺ), “What ALLĀH wills and you will!”
The Prophet (ﷺ) said, “Do you make me equal to ALLĀH? Rather, what ALLĀH wills alone.”
{Musnad Ahmad #1839}