"Whoever receives one little child like this in My name receives Me. Whoever causes one of these little ones who believe in Me to sin, it would be better for him if a millstone were hung around his neck, and he were drowned in the depth of the sea" (Matthew 18:5-6).
The following is a meditation from the blessed pastor Martin Luther...
Thus it is true that parents, even if they had nothing else to do, might attain eternal blessedness through their children. And if they bring them up in the true service of God, they will have both hands full of good works to do. What else are the hungry, thirsty, naked, the prisoners, the sick, and the strangers here but the souls of your own children? It is for their sake that God makes your house a hospital and appoints you the master of it, that you may tend them, feed them, and quench their thirst with good words and works, so that they learn to trust in God, believe in him, fear him, and place their hope in him. This is in order that they will honor his name, neither swear nor curse, be diligent, worship God and hear his Word, learn to despise the kings of this world, bear misfortune meekly, not to fear death or to love this life! Oh, what a blessed home where such parents live. It is indeed like a true church, a select monastery, yes, like paradise.
And again, there is no easier way for parents to merit hell than through their own children, in their own home, when they neglect to teach them these things. What does it help them if they bring themselves to the verge of death through fasting, praying, going on pilgrimage, and doing such works? On the day of judgment God will not ask about such things but will demand of them the children he has given and committed to them (Martin Luther - Day by Day We Magnify You, p. 65).
You may purchase this little book of devotions HERE.