Tell the Truth

Be truthful and consistent when offering rewards and cautioning with punishments

(This hadeeth quoted here is not in verbatim form)

Rasulullah -shallallahu 'alayhi wa sallam said when there was a mother who asked her child to come by saying there's dates for her child: are you really going to give her? the mother answered yes. and He said: you better, if not you are lying. (Hadeeth Abu Dawud, Shahih Al Albani)