Proverbs 4:23

"Above all else, guard your heart, for it is the wellspring of life."

The word "heart" carries a connotation for modern readers of this proverb that Solomon had not intended. To us, the heart is the seat of emotion and desire and love. In context, Solomon speaks of it as the disposition of a child in his choices between righteousness and wickedness. In other words, it's not advice concerning dating/romance or materialism. It's about staying on a straight path, morally speaking (and, of course, the aforementioned have their place in such considerations).

The predominant theme of the chapter is taking the loving, parental instruction one received seriously. This father is encouraging his son to keep to a righteous path. He realizes that the enticements of sinners will be strong, and he assures his son that there is great reward to be gained from living according to wisdom--in the way of righteousness. So the son, who will need moral guidance throughout life, is reminded to keep what his father has taught him at the forefront of his decision making and action.

Godly parents teach their children according to righteousness. By keeping a father's or mother's words in mind and believing it is for their good, wise children "guard" their "hearts." That is, they find protection in their faithfulness to parental instruction, which will translate into godly wisdom, because this wisdom determines the experiences of life.