Charles Spurgeon is one of my favorite writers. Here, his words about the importance of training kids (particularly, the word to those of us who preach) grab my attention:
Youth are susceptible to evil doctrine. Whether we teach young Christians truth or not, the devil will be sure to teach them error. They will hear it somehow, even if they are watched by the most careful guardians. The only way to keep chaff out of the child’s little measure is to fill it to the brim with good wheat. Oh, may the spirit of God help us do this! The more the young are taught, the better; truth will keep them from being misled.
We are especially exhorted to feed them, because they are likely to be overlooked. I am afraid our sermons often go over the heads of the young – who may be as true Christians as the older ones. Blessed is he who can speak in a way that is understood by a child! Blessed is that godly woman who adapts herself in her class to the style of youthful thought so that the truth from her heart streams into the children’s hearts without limitation or hindrance.
Spurgeon, Charles H., Come Ye Children (Updated, Annotated): Obtaining Our Lord’s Heart for Loving and Teaching Children (p. 5). Aneko Press. Kindle Edition.