God has already made us holy. The word "saint" means "holy person." In fact it is the same Greek word used for the holy in Holy Spirit.
1 Peter 1:15 says "as He who
did call you is holy, you also, become holy in all your behavior." So since
we are holy our behavior should be holy.
Calling a child bad for
doing one bad thing leaves the impression that you think they are bad
instead of just what they've done is bad. That is a very damaging thing.
Our behavior is not who we are. So we need to realize that we are holy even though we do not always behave holy.