Children learn best by example.
It is critical to train little ones so they can be taught. . Of course, love is the bottom line. And, real ove will sacrifice the child's approval for what is best for that child.
The first time a child says "no", there should be pretty scary consequences. With girls, it is usually around 1 year. Boys, maybe a little later, but it is one of the first words they learn. A tiny one can be held and face to face, told that may never happen again. In the event of a second time, there has to be a more significant consequence. Perhaps sitting in a chir in the corner. The "No!" coming from the child is one of the most serious offenses a little one can commit, and it is often met with chuckling or it is ignored.
You are not responsible to see it never happens again. You are only responsible to meet it with an appropriate consequence every single time - without fail. Over the years, that is the thing that protects you from the ultimate frustration. Your job is to meet rebellion with a consequence. Different children yield at difference ages; some as adults. The issue is not the fix. The issue is right and wrong and your loving and calm consistency.
Teaching has to do with the Word of God. Who He is. What He requires. Songs and verses learned when children are little stay with them forever.
Most importantly, we raise our children on our knees. They are not ours. They are His. I know wonderful Saints who have given up their children to the Lord hundreds of times. He never promised they would be paragons of virtue growing up.
They must see our lives reflecting the One on whom we rely. Saying all the right Christian things is a ministry of death if there is anger and rebellion in the soul of the speaker.
We always pray that our children may know the New Birth and learn to be Living Sacrifices. It isn't a factory procedure. It means they will go through some hard things.
Soldier, seek out other parents you know are willing to yield their children to the Lord. Establish a weekly time of prayer together. He gets it. You are not alone.
Tell him today. Aloud.