Allah tells us that He is the Owner of all things, and that everything is easy for Him. He has the supplies for all things with Him.

﴿وَمَا نُنَزِّلُهُ إِلاَّ بِقَدَرٍ مَّعْلُومٍ﴾

(and We do not send it down but in a known measure.) meaning, as He wills and as He wants. Doing so out of His great wisdom and mercy towards His servants, in a way that He is under no obligation to do. But He has decreed mercy for Himself. Yazid bin Abi Ziyad reported from Abu Juhayfah that `Abdullah said: "No year has more rain than another, but Allah divides the rain between them as He wills, it rains here a year and there a year. Then he recited:

﴿وَإِن مِّن شَىْءٍ إِلاَّ عِندَنَا خَزَائِنُهُ﴾

(And there is not a thing, but the supplies for it are with Us...) Reported by Ibn Jarir.