Proof for existence of Allah SWT

As Imam ash-Shafi'ee remarked, when asked about the proof for the existence of God: "The leaf of a mulberry tree - its colour, smell, taste and everything about it seem one and the same to you. But a caterpiller eats it and it comes out as a fine silken thread. A bee feeds on it and it comes out as honey. A sheep eats it and it comes out as dung. Gazelles chew on it and it conjeals producing the fragnance of musk. Who has made all these different things coming from the same type of leaf?"

This may not be a few words, but trust me an Athiest would be gobsmacked.

Assalaam Alaikum Wa Rahmatullahi Wa Barakatuh,

A short proof from scholar Bediuzzaman Said Nursi:

" Every village must have its headman; every needle must have its manufacturer and craftsman. And, as you know, every letter must be written by someone. How, then, can it be that so extremely well-ordered a kingdom should have no ruler?


A book, particularly one in each word of which a minute pen has inscribed another whole book, and in each letter of which a fine pen has traced a poem, cannot be without a writer; this would be entirely impossible. So too this cosmos cannot be without its inscriber; this is impossible to the utmost degree. For the cosmos is precisely such a book that each of its pages includes many other books, each of its words contains a book, and each of its letters contains a poem. The face of the earth is but a single page in the book of the cosmos. See how many books it contains. Every fruit is a letter, and every seed is a dot. In that dot is contained the index of the whole tree in its vastness. A book such as this can have been inscribed only by the mighty pen of a Possessor of Glory Who enjoys the attributes of splendour and beauty, and Who is the holder of infinite wisdom and power. Faith, then, follows inevitably on the observation of the world, unless one is drunk on misguidance.
Similarly, a house cannot arise without a builder, particularly a house adorned with miraculous works of art, wondrous designs, and amazing ornaments. As much art has been put into one of its stones as into a whole palace. No intelligence will accept that it could arise without a builder; definitely it needs a master architect. Moreover, within the building, veritable rooms take shape and change each hour with the utmost order and ease, just as if clothes were being changed, or as if scenes were passing across a cinema screen. We can say even that numerous little rooms are constantly being created in each of those scenes.
In like manner, the cosmos also requires an infinitely wise, all-knowing and all-powerful maker. For the magnificent cosmos is a palace that has the sun and the moon as its lamps and the stars as its candles; time is like a rope or ribbon hung within it, on to which the Glorious Creator each year threads a new world. And within the world that He thus threads on the string of time He places three hundred and sixty fresh and orderly forms. He changes them with the utmost orderliness and wisdom. He has made the face of the earth a bounteous spread that He adorns each spring with three hundred thousand species of creation, that He fills with innumerable kinds of generous gifts. This He does in such a fashion that they all stand apart from each other, quite separate and distinct, despite their being at the same time so close and intermingled. Is it possible to overlook the existence of the Maker of such a palace? "

From: http://www.lightofquran.info/10word.htm

the fact that we have everything we need, whether it is food, water, fruit, spices, sugar, wood, metal, oxygen, material for clothing, etc. all of that shows that it all couldn't have happened by itself. Even in the Quran, in Surah Al-Waqiah Allah says:
And have you seen the water that you drink?
Is it you who brought it down from the clouds, or is it We who bring it down? (56: 68-69)

the verses preceding these two verses have more arguments to show that God exists and everything didn't come into being by itself.