The wise father will place before his sons that fact that living according to God's ways and commands is the very best way to live. Living this way is how to experience, "Life and life abundantly" as Jesus said in John 10:10. He will also let them know that God's ways are also the most healthy way to live for their physical bodies as well. This should be almost a "no-brainer" when we grasp that God, Who is omniscient and all-wise, would of course know the very best way for us to conduct ourselves for the most healthy and meaningful life the few years we have on this planet.
The father begins by frankly telling his son that the ways of God are life to those who find them. Jesus warned us in John that the thief, who is the devil, comes to kill, steal, and destroy. We should take note that also in 1 John we read that the world lies in the power of the evil one. Therefore it should be no surprise to us that the world and its ways are destructive to our health and well-being. To follow the world is to ultimately harm ourselves. God made the world around us to function in a certain way. To follow Him is to follow the designer and creator of all that we see and know. When God gave His Law to Israel He said something very powerful in Deuteronomy 30,
"See, I have set before you today life and prosperity, and death and adversity;in that I command you today to love the LORD your God, to walk in His ways and to keep His commandments and His statutes and His judgments, that you may live and multiply . . . I call heaven and earth to witness against you today, that I have set before you life and death, the blessing and the curse. So choose life in order that you may live, you and your descendants, by loving the LORD your God, by obeying His voice, and by holding fast to Him; for this is your life and the length of your days . . ." (Deuteronomy 30:15-16,19-20)
God made it clear to His people that His ways were best - actually they were penultimate over all other ways of living. To love, serve, and obey Him would bring them great blessing and life. Again, He tells Israel this in Deuteronomy 32:46-47 when He says, "Take to your heart all the words with which I am warning you today, which you shall command your sons to observe carefully, even all the words of this law. For it is not an idle word for you; indeed it is your life."
The God who gave these very frank statements to Israel - also commanded the fathers of that nation to impress those same words upon the hearts of their sons. So all we are reading here in Proverbs is a restatement of what God has commanded previously.
The father also seeks to say to his son that obeying the Lord's commands is also "health" to the body. Here is where things get fascinating. I attended Auburn University for my undergraduate work. While there I knew a couple of brothers in Christ who endeavored to study the Scriptures and test the Old Testament dietary laws to see why God gave them. Later I also read extensive articles out of a ministry in Chicago where doctors began treating patients based upon God's dietary and cleanliness laws. Both groups adamantly stated to me that what God gave in the Old Testament is the most astounding public health system known to mankind. If these commands were followed, it would lead to a marvelously healthy society. When the Jewish slums followed these laws in Europe - the beubonic plague did not affect their populations. Another way to say this is - the commandments of God are health to our bodies.
Dads, we need to speak frankly to our sons concerning life - and what enhances and offers life to them. The world will not tell them such things, in fact, the world will tell them the opposite. We are the ones God has designed to speak such things to them. Actually, we are commanded to do so. Blessed is the son who has a wise father who will speak frankly with him about life - and life abundantly!