How can an atheist be invited to Islam, and how can the meaning of "Lā ʾilāāh ʾillā-llāh" (There is no god but Allah) be explained to him?

A Muslim should not engage in da'wah, especially with atheists, unless they possess sufficient Islamic knowledge and rational arguments to refute misconceptions. First, one must equip themselves with Islamic knowledge, then learn how to respond to the atheists' misconceptions.

To refute atheists who deny the existence of God, one should demonstrate to them, using innate, rational, and scriptural arguments, the impossibility of an ordered world existing without a wise Creator who possesses absolute power and self-sufficiency. Then, one should explain the meaning of "La ilaha illallah" (There is no god but Allah), clarifying that the wise Creator did not create His creation in vain, but for a noble purpose: to worship Him alone, without any partners. This is the innate disposition upon which people were created. The meaning of "La ilaha illallah" is: there is no true deity worthy of worship except Allah Almighty, for He alone is deserving of worship because He is the Creator and Innovator of the universe.