How can I be sure of the existence of Allah (God)?

The evidence for the existence of Allah Almighty is of two types: read evidence in the clear verses that Allah revealed in His Noble Book, and visible evidence found in contemplating and reflecting upon the vast universe and the human self. Allah Almighty has urged reflection upon this universe and the understanding of its secrets to believe in Him, clarifying that the existence of creatures necessitates the existence of a Creator for them. Humans, the heavens, and the earth exist, and they must have a Creator and Sustainer. Once the existence of the Creator is established, His worship and drawing near to Him become obligatory.