Imam Sadiq (as) Debate with an Eygptian Athiest

Hisham b. al-Hekem narrated, saying: [An Egyptian atheist came to know that Imam Abu ‘Abd Allah had knowledge. So he went to Medina to debate with him. He did not find him. He was told that the Imam was in Mecca. So he went to it and met him. He approached and greeted him. Then Abu ‘Abd Allah (al-Sadiq) asked him:]
- What is you name?
- ‘Abd al-Malik.
- What is you kunya?
- Abu ‘Abd Allah.
-Who is the king whose servant is you? Is he among the kings of the earth or among the kings of the heaven? Tell me about your son: Is he the servant of the heaven god or of the earth one?
The atheist kept silent and was unable to answer. So Abu ‘Abd Allah said to him: “Say!” The atheist became perplexed. So the Imam, peace be on him, looked at him and said to him: “After you have finished circumambulating the Kaaba, come to me.” When the atheist had finished circumambulating the Kaaba, he went to the Imam. The Imam, peace be on him, asked him:
-Did you know that the earth has bottom and top?
-Did you go to its bottom?
-Did you know what was beneath it?
-I did not know. However, I imagine that there is nothing beneath it.
-Imagination is feebleness unless you are sure.
-Have you ascended to the heaven?
-Do you know what is therein?
-Have gone to the east and the west and seen what is beyond them?
-Therefore, I wonder at you! You have not gone to the east and the west. You have not descended to the bottom of the earth, nor have you ascended to the heaven. You have not come to know what is there and what is beyond them. Nevertheless you have denied what is in them. Does the sane deny what they do not know?
-None has told about that except you!
-Therefore, you have doubt about Him. Perhaps, He is He. And perhaps, He is not He.
-Fellow, he who has no knowledge has no proof over him who has knowledge; and the ignorant have no proof over the knowledgeable. O brother of the inhabitants of Egypt, learn from me! Do you not see that the sun and the moon, day and night alternate and do not precede each other? They go and do not return. They are forced. They have no place except their place. If they could go and not come, (they would do). If they were not forced, then why did night not become day, and day (become) night? O brother of the inhabitants of Egypt, by Allah, they are forced. Surely the thing in which you believe and of which you have an imagination is of time. If it was it that which made them go, then why did it not make them return? If it made them return, then why did it not make them go? Do you not see that the earth and the heaven are raised? The heaven does not fall on the earth, nor does the earth slope down that which is beneath it. By Allah, their Creator and Manager has caught them.
The Egyptian kept silent and was unable to give an answer. He thought of the dimensions of the words of the Imam. He found in them guidance and truth, so he returned to correctness. He declared his faith and became Muslim.( Al-Tabari, al-Ihtijajj.)