Jesus said in John 10:10 that He has come to give life in abundance because He is life and the giver of life as He also said in John 11:25 that I am the resurrection and the life. The instruction to go into the world to preach the Gospel is an instruction to go and give the life of Jesus you had received. The only reason people are not going into the world to preach the Gospel is because they are not receiving life hence do not have (eternal) life in them. You can not give what you do not have. Those who give love, joy, peace,hope etc to others do so because they are rich in it. God is inexhaustibly rich in all good things that He gave His own precious life to redeemed the worthless life in mankind. He/she that is giving sweetness to bitterness is a salt and he/she that is shinning light is a light.