"Why not a proof/Sign/indication" - challenge and various responses to it in Quran.

[drfuzzy]

Nothing that comes out of the Quran, the Bible, or any other printed source in any language constitutes proof.

You are right. Hold your horses. You will see that God is very precise with what he says constitutes proof.

The only way I will accept proof as "he says" is if HE shows up and proves it.  On international TV.  In the presence of multiple teams of reputable scientists.  And even then, I won't necessarily accept whatever this entity says as proof that it is worth "worship".  In fact, any entity that demands worship is automatically unworthy to receive it.