Bible Verses About Self-Denial: Danger of neglecting

for whoever may will to save his life, shall lose it, and whoever may lose his life for my sake shall find it,

for what is a man profited if he may gain the whole world, but of his life suffer loss? or what shall a man give as an exchange for his life?

but I chastise my body, and bring it into servitude, lest by any means, having preached to others--I myself may become disapproved.