Jesus gives us an important reflection about the wisdom of God:"You are the salt of the earth. But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled underfoot. You are the light of the world. A town built on a hill cannot be hidden. Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house", Matthew 5:13-15.
Wisdom in the Gospels is called in various ways, is called the key of ciencie (Luke 11:52), is also called the salt of the world (Matthew 5:13).Jesus compared himself to the door of salvation in reference to living wisely (John 10:9).
Why is the wisdom compared with the salt? Because the wisdom responds to the desire for the good. The desire for the good is the taste for wisdom, is also desire of improvement. The wisdom as the salt has it's own flavor (taste for the divine things). The wisdom as spiritual gift is the love for the true and the virtue. As sciencie is the knowledge of the ultimate causes (Aristotle).
Since Wisdom is both science and  perfect virtue or spiritual gift, this make wisdom have two sources: experience, for example: the architect did wisely his work; and on the other hand the divine inspiration.
Inspired wisdom has its origine in the gift of counsel: perceive with attention, meditate with intuition and inspiration and decide with creativity. The gift of counsel has two characteristics: precision and accuracy, the counsel seeks the truth. The Bible is the fruit of this gift, that is why we say that the Bible is a book inspired by the Word of God; the Word, it is understood that is everything that comes from the sacred listening.
Inspired wisdom can only be taught by a doctor of wisdom, that is, a person gifted by the action of God. Philosophy is a science, the person who knows about philosophy is called doctor in philosophy, just as the doctor of medicine is who knows about medicine. The wisdom is a science like philosophy and medicine, the person capacítate to teach wisdom is the doctor of wisdom. King Solomon is a doctor of wisdom in the old testament. Solomon aquires wisdom asking for it to God: "Give your servant a heart that knows how to listen", 1 King 3. The Bible teach us that wisdom comes from listening.
Being the salt of the earth means to instruct wisdom. Speak about wisdom, is speak about God.
Being the light of the world means being a guide or having a guide, we walk or work when there is light, what can be done in the dark?. To instruct in wisdom is to give guidance, direction to things, such as the beatitudes that are the fruit of wisdom and constitute a guide to life.
We are called to be the salt of the earth and light of the world.