One of the verses I had written down to pray on for my unborn. It is also a commitment to bring up that child in the ways of God and let God use the child however he pleases.
The Bible tells us that Hannah handed Samuel over to God without hesistation. Considering the fact that she had prayed for so long for the fruit of the womb. Many of us did not exactly pray for that long for a child, but at the point of marriage, we probably agreed to have kids or were prayed for (prayers of fruitfulness etc). Either way, we owe it to God to bring up our children in the way of the Lord.
Allow your children participate in church activities, outreaches and general service to God. There is nothing more rewarding.