The Kingdom of God begins with the inward park of a man, but it doesn't stop there. It goes from what you are to what you do.
The humanistic ethical systems working from the outward to the inward, end in futility. However, the heaven born system, meaning the Kingdom of God is working from the inward to the outer ends in fruitfulness, and fruitfulness on a universal scale. The Beatitudes are followed by this statement from King Jesus. You are the salt of the earth; but if the salt loses its flavor, how shall it be seasoned? It is then good for nothing but not be thrown out and trampled underfoot by men. You are the light of the world. A city that is set on a hill cannot be hidden.
The idea of a homeless man telling a group of fishermen that they were to be salt to the earth and light to the world is grandiose or vaporing (meaning, trying to show off) or else it is the unfolding of the grand design; the Kingdom of God on earth. It was the cosmic or comic. The ages say that it is the cosmic.
If you notice, Jesus stated that they were the salt of the earth, not that they would be. God had already seen and prepared the end. Jesus the king knew that His words would transform their lives. Remember this one thing: the Kingdom of God is His Spirit living in your mortal body. For the Kingdom of God is not eating and drinking, but righteousness and peace and joy in the Holy Spirit. The Holy Spirit makes you an authentic citizen of the Kingdom, not attending your religious church services every Sunday. Remember, in order for you to be effective, you must be filled with His Spirit. But you shall receive power when the Holy Spirit has come upon you; and you shall be witnesses to Me in Jerusalem and in all Judea and Samaria and to the end of the earth. This power comes through submitting to His Word.
Matthew 5:13-14 Romans 14:17 Acts 1:8