Here Allah tells of His perfect might and power in His creation and subjugation of all things.

[أَوَلَمْ يَرَ الَّذِينَ كَفَرُواْ]

(Have not those who disbelieve known) means, those who deny His Divine nature and worship others instead of Him, do they not realize that Allah is the One Who is Independent in His powers of creation and is running the affairs of all things with absolute power So how can it be appropriate to worship anything else beside Him or to associate others in worship with Him Do they not see that the heavens and the earth were joined together, i.e. in the beginning they were all one piece, attached to one another and piled up on top of one another, then He separated them from one another, and made the heavens seven and the earth seven, placing the air between the earth and the lowest heaven. Then He caused rain to fall from the sky and vegetation to grow from the earth. He says:

[وَجَعَلْنَا مِنَ الْمَآءِ كُلَّ شَىْءٍ حَىٍّ أَفَلاَ يُؤْمِنُونَ]

(And We have made from water every living thing. Will they not then believe) meaning, they see with their own eyes how creation develops step by step. All of that is proof of the existence of the Creator Who is in control of all things and is able to do whatever He wills.