Is the statement of one who says: "We believe in God assuming His existence; for if He exists, we have won, and if He does not exist, we have lost nothing," considered disbelief (kufr), and how can he be convinced?

The existence of God is an innate truth attested to by both religious and cosmic signs, and affirmed by a sound intellect. The faith of no one is valid until he firmly believes in God's existence. Every created thing must have a creator, and the created thing does not create itself. Allah Almighty says: "Were they created by nothing, or were they themselves the creators? Or did they create the heavens and the earth? Rather, they are not certain." (Qur’an 52:35-36). Furthermore, the order of the universe indicates a director behind it, such as the sun and the moon, as exemplified by Abraham's debate with Nimrod, and the story of Abu Hanifa regarding the ship. Allah Almighty says: "We will show them Our signs in the horizons and within themselves until it becomes clear to them that it is the truth." (Qur’an 41:53). Whoever denies the existence of God is defiant to both intellect and innate disposition (fitra).