Deuteronomy 6:6-9 (NKJV)
And these words which I command you today shall be in your heart. You shall teach them diligently to your children, and shall talk of them when you sit in your house, when you walk by the way, when you lie down, and when you rise up. You shall bind them as a sign on your hand, and they shall be as frontlets between your eyes. You shall write them on the doorposts of your house and on your gates.
To be "In your heart" means to be at the center of your innermost being. Your primary job as a parent is to impart truth to your children. Why talk small talk when you can talk about the things of God. God's truth ought to permeate every part of your life. Before you go to sleep, God's word should be your last thoughts. When you wake up, you are reminded of your Creator. Everything you touch is part of God's creation. Everything you look at should be filtered through the lens of God's truth. When people come in to your house, it ought to be self-evident whom you serve. Your primary mission as you go out into the world ought to be as a witness to God's work in your life.