Sin

 
Therefore to him that knoweth to do good, and doeth it not, to him it is sin.
This verse challenges me to put others first. If I know that someone needs help and I won’t do it because I want to do something for myself or go somewhere pleasing to me, then I have committed sin before God. Jesus never did things to please Himself, but He always did those things that pleased His Father. We should do the same.