An-Naḥl: 71
"And Allah has favored some of you over others in provision..."
Meaning: He has made you unequal in provision. He has provided you with better than what He has provided your slaves, even though they are human beings like you and your brothers. Therefore, you ought to share the surplus of what you have been provided with them, so that you may be equal in clothing and food.
As it is narrated regarding Abu Dharr, that he heard the Prophet (ﷺ) say: "They are but your brothers; so clothe them with what you wear, and feed them with what you eat." After that, his slave was never seen except wearing the same cloak and lower garment as him, without any difference.
"...Do they then deny the favor of Allah?"
He categorized this [refusal to share] as a form of denying His favor.
It is also said: This is a parable Allah struck for those who set up partners with Him. He said to them: "You do not make your slaves equal to yourselves in what I have bestowed upon you, nor do you make them partners in it, and you would not be pleased with that for yourselves. How then are you pleased to make My slaves partners with Me?"
It is also said: The meaning is that both the masters and the slaves—I am the Provider for them all; they are equal in My provision. So, let not the masters think that they are giving their slaves anything of provision from their own possession. It is only My provision, which I cause to reach them through their hands.
(Note: The word "yajḥadūn" [they deny] is recited with both the 'tā' [you] and the 'yā' [they].)
"And Allah has made for you mates from among yourselves, and has made for you, from your mates, sons and grandsons, and has provided you with good things. Do they then believe in falsehood and deny the favor of Allah?"