Biblical obedience is first and foremost a response to God’s mercy. As people in need of the grace of God there is nothing we can do nothing to earn our standing with God. Obedience doesn’t make a person good, it is a response to God’s goodness. Do your children believe this?
Obedience can’t be used to plea bargain with God, or to appease him, or to become worthy in his eyes. Only the work of Christ can make things right with God.
Understood in this light, obedience is not something you use to gain a reward – obedience itself is your reward, your great privilege, honor and joy. If that is true for you, then that is also the attitude you want to convey to your children. God commands them and you to do good things. But doing good things doesn’t make a person good.
Just as I cannot make myself more acceptable to God by my obedience, neither do I want my children to think that I will be more accepting of them because of their obedience. It is true that an obedient child may easier to live with than a disobedient one. But obedience cannot be the grounds of my acceptance of my children. God loves and accepts me because of what Jesus did. You are to love and accept your children because God gave them to you and commanded you to love them and raise them to honor him.
If your children think that obedience is necessary to gain your acceptance, this will produce stress and instability in the relationship. Their security will be connected to how well they think they are performing. When children disobey, the solution should not be to do better next time. The solution is to trust Christ for the strength to do what cannot be done in their own strength.