Bereshit 

בראשית

What did Rabbi Akiva respond to a person who sought unequivocal proof of the existence of a Creator? 

It happened that a heretic came and said to Rabbi Akiva: This world – who created it? Rabbi Akiva said to him: The Holy One, blessed be He. The heretic said to him: Show me some clear proof! Rabbi Akiva said to him: Come to me tomorrow. The heretic came to him the next day. Rabbi Akiva said to him: What are you wearing? He said to him: A garment. Rabbi Akiva said to him: Who made it? The heretic said to him: The weaver. Rabbi Akiva said to him: I don’t believe you; show me some clear proof. The heretic said to him: And what should I show you? Don’t you know that the weaver made it? Rabbi Akiva said to him: And you, don’t you know that the Holy One, blessed be He, created His world? That heretic took his leave. Rabbi Akiva’s students said to him: What is the clear matter? Rabbi Akiva said to them: My children, just as the house attests to its builder, and the garment attests to its weaver, and the door attests to its carpenter, so the world attests to the Holy One, blessed be He, that He created it. <source>(Otzar HaMidrashim [Eisenstein], Temura, p. 583) </source>