Look around and contemplate the signs that are present in the creation. The brook, the tree, the flower, the mountain, the earth and the sky, the sun and the moon, the day and the night --- they will all remind you of the Creator of all things. Thus your faith will increase and so will your degree of righteousness.
(Then take admonition, O’ you with eyes (to see).) (Qur’an 59: 2)
A philosopher who embraced Islam said:
“Whenever I was beset by doubts, I would look at the book of creation, the letters of which spoke of miracles and ultimate skill. Then my faith would not only return to normal, but it would increase as well."