When you look at your own condition before a Holy God, you recognize that without Christ, you are a completely helpless, vile sinner, right? Our children are in the same state. They need a Savior, THE Savior, and the sooner they realize this, the better.
John MacArthur (and he says it all much more eloquently than I can so I'll just quote him), explains it this way in his book, What The Bible Says About Parenting Biblical Principle For Raising Godly Children,
"Every child comes into the world with an insatiable capacity for evil. Even before birth, the human heart is already programmed for sin and selfishness. Humanity's relentless penchant for every kid of depravity is such that, given free reign, every baby has the potential to become a monster.
Although the outworking of the sin nature does not necessarily attain full expression in every person's behavior, it is nonetheless called total depravity because there is no aspect of the human personality, character, mind, emotions, or will that is free form the corruption of sin or immune to sin's enticements."
In the New Testament, Paul writes,
"Through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned" Romans 5:12
MacArthur goes on to say, "Left to themselves, they will pursue a course of sin. And left entirely to themselves, there is no evil of which they are incapable. "
Psalm 58:3 says, "The wicked are estranged from the womb; they go astray as soon as they are born, speaking lies."
Wow - does that paint a vivid picture of our children's hearts or what? I know that it is hard to think of our children as depraved, but they are. It is our job as their parents to make them aware of this sinful condition, show them that there is nothing they can do about it, and direct them to the cross.
Do you do that? Are you teaching your children that they are sinners?
When a child is getting into trouble for the umpteenth time for the same thing, they seem just as frustrated as we are about it? Use this opportunity. Tell them about their heart condition. Tell them they cannot "fix it" by themselves. Direct them to the cross. Tell them about Jesus and how He has the power to free them from their sinful condition.
Further in the chapter, John MacArthur says,
"Your top priority job as a parent, then, is to be an evangelist in your home. You need to teach your children the law of God; teach them the gospel of divine grace; show them their need for a Savior; and point them to Jesus Christ as the only One who can save them. If they grow up without a keen awareness of their need for salvation, you as a parent will have failed in your primary task as their spiritual leader.
Note this, however: Regeneration is not something you can do for them. Parents who force, coerce, or manipulate their kids may pressure them into a false profession, but genuine faith is something only divine grace can prompt. "
Paul in the New Testament says,
"How shall they believe in Him whom they have not heard? And how shall they hear without a preacher?" Romans 10:14
MacArthur goes on to say
"As believing parents, you are the first and most important preachers God has given them.
They [your children] will observe your lives up close, to see if you seriously believe what you are teaching them. They will weigh what you teach them about these matters from the earliest time they can understand anything. You have a better opportunity than anyone to help frame what they know about Christ.
Every moment of their lives is a teaching opportunity (Deuteronomy 6:6-7), and you should use those opportunities to the best advantage for your kids' sake." [emphasis added]
So let's embrace each opportunity of diobedience as an opportunity to show them the grace and forgiveness they can receive at the cross.