As you parent, consider this way of thinking:
Imagine a personified version of the sin in the heart of your child as something that wants to thrive. It doesn’t want to die. So it is tries to protect itself by building a shell that will protect it from the attempts of a parent to be God’s agent in training the child in the way he should go. We should know as parents what might strengthen or feed that shell.
I believe that Anger is one of these things.
And one of the most significant ways that a parent can add to this anger is to discipline a child and leave it unresolved, so that the child is still angry when you leave the room (or the situation, or the conversation). This anger then serves the sin by providing material which it can use to build the shell that it (Sin) is creating around its place in the heart of a child.
Often (Usually? Always?) the child is angry after discipline because he believes that injustice has been done to him. It doesn’t matter how careful and just you were in the discipline of the child if the child thinks you were unjust. The child’s sinful nature will use this to put a wall against future training or spiritual guidance.
“Why should I be good if I just get punished anyway?”
“They only warned me twice”
“I can’t be held responsible for behavior I can’t control.”
A two year old (or a five year old or an eight year old) won’t think these words in their minds, but they think these ideas. And you need to show them that, yes, in fact they did know what they were doing, or yes, they could have controlled themselves, or no, their Dad isn’t being mean for mean’s sake.
Disciplining the child in the wrong way may be worse than not disciplining them at all. Don’t contribute to sin’s shell.