Sometimes children do not follow the example of their parents. It is worth noting that in children, the example and modeling of their parents is essential for their proper development. Children need the example of their parents in order to learn about life and how to react to the circumstances presented to you.
They feel disconnected from us
When children do not follow our example, it is often because they feel disconnected from us. Why would your child feel disconnected? Because he was away from you all day. Or you lost your temper with him this morning. Or he's mad at you because you always have the baby on your lap.
Or rely on timeouts and consequences for discipline, rather than connection. Or maybe just because he is a small person in a big world, and that is scary, and all those feelings of fear are pushed in, where they block the child's ability to lovingly connect.
What can be the solution?
Consistently rebuild the connection by empathizing with your child's experience, when you're giving a directive, and as often as you can. Prepare for feelings of upset to arise once your child feels that warm connection more strongly, and remain compassionate during the resulting meltdown. Later As soon as you have had the opportunity to "show" the annoyance that has been affecting him, your child will feel reconnected and cooperative.
Remember that your child needs to feel connected to you all the time, so use assertiveness and empathy whenever you have the opportunity for your child to feel understood and accepted all the time. You will see that in this way your child will never feel disconnected from you again. And neither are you from him!