"I dont know. Coz I never see Him"

In The Name of Allah The Most Gracious The Most Merciful

A Muslim ask a tourist which is an atheist when he comes to masjid for a visit.
"Why do you  not believe in god?"
"I dont know. Coz I never see Him."
"You may go to the church, temple and they can show you god. But I'm sorry, I cant show you god. Because He is beyond His creation. Nothing cant be compared to Him. We cannot put any image into Him because anything that we can imagine, it's all His creation. Sir, do you know how's this universe come?"
"I dont know..."
"But I know. Its stated in this Book(Quran) which is given to prophet Muhammad 1400 years ago in the desert who cannot read and cannot write. Dont you think it's a miracle?"

"Do not the Unbelievers see that the heavens and the earth were joined together (as one unit of creation), before we clove them asunder? We made from water every living thing. Will they not then believe?"

(Al-Anbiya:30)

Then the atheist starting to ask about god. That is how we can approach the atheist. They can be convinced with modern science and facts. Then they will start to think that there's must be 'something' above who created this.

For example Antony Flew, a British philosopher, Oxford professor, and leading champion of atheism for more than fifty years, honestly followed the evidence and renounced his naturalistic faith in 2004. In a published interview with another philosopher, Flew said, "My whole life has been guided by the principle of Plato's Socrates: Follow the evidence, wherever it leads."

After chewing on his scientific worldview for more than five decades, Flew concluded, "A super-intelligence is the only good explanation for the origin of life and the complexity of nature."

Previously, in his central work, The Presumption of Atheism (1976), Flew argued that the "onus of proof [of God] must lie upon the theist." However, at the age of 81, Flew shocked the world when he renounced his atheism because “the argument for Intelligent Design is enormously stronger than it was when I first met it." In his same 2004 interview, Flew shared, "It seems to me that the case for an Aristotelian God who has the characteristics of power and also intelligence, is now much stronger than it ever was before."

The story of Antony Flew reminds us that physics and metaphysics are not mutually exclusive. True science asks us to follow the observational evidence, no matter what the destination. Does life really occur in a naturalistic vacuum? Or do its design, order, and complexity necessitate something more?

Antony Flew is an honest thinker who ultimately acknowledged the existence of God. Like many of us, recognition is a huge step. However, when it comes to the questions of God, purpose, meaning, origins, and destinies, can we rest in mere recognition? What about Dr. Flew’s observations of Intelligent Design -- the immensity, intensity, and intricacy of it all -- don’t they compel us to move forward and seek additional signposts for truth in our life journeys?

"Kami akan memperlihatkan kepada mereka tanda-tanda (kekuasaan) Kami di segenap ufuk dan pada diri mereka sendiri, sehingga jelaslah bagi mereka bahwa Al Qur'an itu adalah benar. Dan apakah Tuhanmu tidak cukup (bagi kamu) bahwa sesungguhnya Dia menyaksikan segala sesuatu? Ingatlah bahwa sesungguhnya mereka adalah dalam keraguan tentang pertemuan dengan Tuhan mereka. Ingatlah, bahwa sesungguhnya Dia Maha Meliputi segala sesuatu. 

(Al-Fussilat:53-54)

*Atheism is traditionally defined as disbelief in the existence of  God. As such, atheism involves active rejection of belief in the existence of God