Teach your children to pray. Teach them from as early an age as you can. Let them know how normal it is to pray and watch God answer. Let them watch you pray and sing and encourage people. They will hear what you say, but they will learn what they see.
The faith of children is truly dynamic, as in “relating to physical force or energy”. Their faith is not filtered or adulterated with bad philosophy or theology. It’s pure power, because truth is truth to them.
Show them how to ask God for what they need. Include them in family prayer. Let them pray over their friends and their pets. Never, never prevent them from praying for you. If you’ve never had a child pray for you, you have no idea how powerful it is.
Don’t assume that you have to teach children a watered down version of the gospel. The same Holy Spirit that raised Christ from the dead is theirs as well. God loves to partner with kids, and they will see Him work in amazing ways. Let them pray for healing. Read them stories in the Bible about how God used children and encourage them to trust God. The earlier the better. Those are the kids that will be world-changers.