God is all Knowing.
Whenever we talk well about a person, do a good deed for person, or think highly about a person, we are doing it as unto God...”for as much as you do it unto these, my little children, you do it unto me”. Never be deceived into thinking that we can talk about God behind His back, nor do our deeds hid from His all seeing eye, nor think thoughts that He does not know! When we speak ill of person, lambast a person, criticize or ridicule a person God knows it and considers it a personal affront. We are to deal with people as Jesus would deal with them, for as believers we are to be His representatives in this world.