... he who is a philosopher or lover of learning, and is entirely pure at departing, is alone permitted to reach the gods. And this is the reason, Simmias and Cebes, why the true votaries of philosophy abstain from all fleshly lusts, and endure and refuse to give themselves up to them—not because they fear poverty or ruin of their families, like the lovers of money, and the world in general; nor like the lovers of power and honor, because they dread the dishonor or disgrace of evil deeds.

Plato - Phaedo