My Mum used many 'sayings' she used to teach us/keep us in line.
There was, of course, the Biblical 'spare the rod and you spoil the child'
She also had many others like:
cut your suit according to your cloth = live within your means
cow doesn't miss its tail until fly season is here = we don't appreciate something/somebody good until its/they are gone
Any parental homespun philosophy you have found useful in life?