Why Are We Here?
There are two prevailing theories in the world about our purpose in life. One is that we are the chance product of a long line of selected mutations, the result of a natural but purposeless process that began billions of years ago for no apparent reason. In that view, there is no "why" for why we are here, so we ought, simply, to make the best of the limited years we have before we die. The other view is that there is a God or designing intelligence who brought the universe into existence, and that humans are here for a purpose.
Since Christians believe that God has revealed Himself to us in the Bible, we also believe He has revealed the purpose for human beings in general and for you in particular. In Genesis 1:26 God said that humans were created in God's likeness, and that as men and women they were to have "dominion over the fish of the sea and over the birds of the heavens and over every living thing that moves on the earth," and also over "every plant yielding seed" and "every tree with seed in its fruit". Humans were to be the caretakers of creation, living in community with their Creator.
Since the moral choice the first man and woman made, to follow their own path rather than God's, creation and humanity's purpose within if has been lost to most people. By nature we don't know as clearly as our first parents why we are here, and even when we do know what we should do, we often choose not to do it. Instead of loving each other, we distrust, hate, and even hurt each other. Instead of binding with a mate for life and creating a family, we end up using sex for personal pleasure. Instead of loving and serving God, we seek to love and serve ourselves.
The 10 Commandments that God gave to the Israelites show the kind of people God created us to be. Living according to those commands is God's will for our lives. But because of what the first two humans, Adam and Eve, did, living out that purpose is a burden and not a joy. Christ Jesus was sent into the world to remove the burden and guilt of not being able to please God and so live out a purposeful life. By His life and death He atoned for our failing to live up to our purpose, and by His resurrection He became a new human being who did fulfill God's intended purpose for us. All Christians who cling to Jesus in faith are declared to be part of that new human being, strengthened to live lives of purpose in preparation for the perfect new creation that is yet to come.