Why?
As a Christian we believe it is our duty to minister to the needs of those less fortunate than we. It is spelled out very clearly in the bible. Look in Isaiah 58:7, Hebrew 13:3, James 2:15-16, and the most clear of all, Matthew 25:40, "And the king shall answer and say unto them, Verily I say unto you, In as much as you have done unto one of the least of my bretheren, ye have done it unto me." (KJV) To get the full meaning of this passage read Matthew 25:31-46.