The reason we need to heed the call to wisdom is because by living a life according to God's wisdom - we will be led to trust in the Lord in all that we do. Seeing life from God's perspective will inevitably lead us to a point where we trust His worldview rather than any other one that is put before us. This is what the father is seeking to teach his son. It is what the wise man is seeking to teach those who lack wisdom. They are trying to make it clear that God's ways are infinitely superior to those of man. They are attempting to show the young and the old that there is a radical difference between the ways of the world and the ways of God.
Trusting in God means having a confidence in Him. It means standing firm in the principles we see taught in Scripture - even when many others are turning to worldly principles. From what we've already seen in this section of verses - this is a far better way to live - one that is pleasant and good. But ultimately to live this way we will also have to be able to speak this way - even at times defending the way that we live to those who think it is foolish and stupid. This is why the father has taken the time to call his son to apply his heart to wisdom and knowledge. It is why he is trying to get his son to think and to reason according to what God says in His Word. It is why he is so adamant in getting his son to meditate and ponder the truth of God deep in his thoughts.
The man teaching either this son, or the unlearned one in God's wisdom - is teaching in a very concrete direction. When he tells his son that he has "taught" him each day - the word he uses means not just to impart information. He is teaching with a purpose. "Yada" is the Hebrew word he uses - and it means to know something. The knowledge though is not just information to pass a written test. It is to know so as to perceive, disciern, and eventually experience something. Thus this teaching is meant to bring his pupil to a point of experiencing God at work in his life. One of the things that this type of teaching moves toward is that people would consider what is said. This means they are doing far more than hearing and doing it. They are considering what is said - it makes them think and reason. They begin to perceive that God is at work in the world - and that He has specific wisdom for them which will teach them how to live in this world. They begin to discern things around them. They see that things are different - choices lead different directions - actions and attitudes lead to a way of living - a lifestyle. They see that God wants to meet them in their everyday experiences - that He is interested in ALL that they do.
God wants to move us from merely practicing a religion or holding religious views - to a life that considers God when they make decisions and live their lives. He wants us to see ALL of life in His way - which we will learn is the way of Life itself. He desires for us to see His way in the midst of all our choices - and to see His way as the very best way. Oh that we would teach our sons - teach those around us such wisdom. That we would call them to so much more than just a Sunday morning religion. We need to call them to see and experience God in all of life - all that they do - all that comes their way. This is the call to wisdom - in effect it is a call to know, love, and experience God in every day. May we not only heed such a call - but also learn wisdom so that we may call others as well.