I often think that God created human beings. Life is indeed very strange and unique. Consider the simple instance of my holding this glass of water and drinking from it. No elephant or tiger nor the solar system or any star can perform this feat. Only a human being can achieve this. Only a human being can think and know that this is water. The Big Bang occurred in the universe 13 billion years ago. Only a human being can conceive an event which occurred 13 billion years ago. The ripples from the Big Bang are spread throughout the universe. Seeing this, a scientist remarked: "It is like seeing the handwriting of God." With space telescopes, astronomers mapped this radiation from the Big Bang; and a scientist exclaimed looking at it: "It is like seeing the handwriting of God."
         Only a human being can think of what happened 13 billion years ago. This requires imagining a process that took place 13 billion years back in time. God has indeed blessed humans beings with unique abilities. Thankfulness for such a God is another name for love of God. When you think in this way, an ocean of thanksgiving wells up inside you. You exclaim: "O God, you have created such a vast universe only for human beings!" Then you develop feelings of love for all mankind. The Prophet said about a Jew: "Was he not a human being?" (Sahih al-Bukhari 1312) 
First you develop an ocean of love for God, and then you develop deep feelings of well-wishing for other human beings. Then, such a person engages in dawah work with great zeal: you do not want any person to remain unaware of the truth when he dies. You do not want any person to be touched by the Fire of Hell. This is an indication of one's faith -- you should be restless to save people from Hellfire and have them admitted in God's mercy.  All this follows after a person has discovered God deeply.