Man's purpose, according to the Bible: The purpose of man is to glorify God and to enjoy Him forever. 1 Corinthians 10:31 says So, whether you eat or drink, or whatever you do, do all to the glory of God. (not self),
Watch God do great things in our lives. God's purpose for creating man: It was, and it is, Love for sharing love; additionally, when God created His people. He gave us good work to do, so we might experience God's goodness and reflect His image in the way we care for one another.
I believe that God placed a purpose in each of us. To serve and show the love of Jesus to all people. We should not think of ourselves as anything higher than servants for Jesus' glory, and always for our good and those with whom we share the word of God.
We can help with kingdom building by living righteously, Matthew 6:33 says, "Seek ye first the kingdom of God, and His righteousness (not our righteousness; this is where confusion comes in at times), and all these things shall be added unto you, God's will and His word, and our good.