How can we refuse Him?

Today I look at Him and see that He has nothing.  He gave everything for me, his possessions, his reputation, and his life for me.  How then can I be unwilling to give Him a few hours of my life to lead a group in spiritual reflection, or feeding the poor.  How can I say I've already given enough this week when someone asks me for money.  How can I be afraid to speak my mind in public concerning what I believe?  How can I refuse when a priest asks me help with anything?  A priest asking us to help is as close to God asking us to help as we are likely to get, how can we refuse him?