There is a Sign and a Blessing in Matters of People's Livelihood
Allah explains to the idolators the ignorance and disbelief involved in their claim that Allah has partners while also admitting that these partners are His servants. In their Talbiyah for Hajj, they used to say, "Here I am, there are no partners for You except Your own partner, You own him and everything he owns." Allah says, denouncing them: `You would not accept for your servant to have an equal share in your wealth, so how is it that Allah would accept His servant to be His equal in divinity and glory As Allah says elsewhere:
ضَرَبَ لَكُمْ مَّثَلاً مِّنْ أَنفُسِكُمْ هَلْ لَّكُمْ مِّن مَّا مَلَكَتْ أَيْمَـنُكُمْ مِّن شُرَكَآءَ فِى مَا رَزَقْنَـكُمْ فَأَنتُمْ فِيهِ سَوَآءٌ تَخَافُونَهُمْ كَخِيفَتِكُمْ أَنفُسَكُمْ
(He sets forth a parable for you from yourselves: Do you have partners among those whom your right hands possess (i.e. your servant) to share as equals in the wealth We have granted you, those whom you fear as you fear each other) (30:28) Al-`Awfi reported that Ibn `Abbas mentioned this Ayah, saying, "Allah is saying - `If they did not want their servant to have a share with them in their wealth and wives, how can My servant have a share with Me in My power' Thus Allah says:
أَفَبِنِعْمَةِ اللَّهِ يَجْحَدُونَ
(Do they then deny the favor of Allah)" According to another report, Ibn `Abbas said: "How can they accept for Me that which they do not accept for themselves"
أَفَبِنِعْمَةِ اللَّهِ يَجْحَدُونَ
(Do they then deny the favor of Allah) meaning, they assign to Allah a share of the tilth and cattle which He has created. They denied His blessings and associated others in worship with Him. Al-Hasan Al-Basri said: "Umar bin Al-Khattab wrote this letter to Abu Musa Al-Ash`ari: `Be content with your provision in this world, for the Most Merciful has honored some of His servants over others in terms of provision as a test of both. The one who has been given plenty is being tested to see if he will give thanks to Allah and fulfill the duties which are his by virtue of his wealth..."' It was reported by Ibn Abi Hatim.
Tafsir Ibn Kathir (abridged, English).