In many ways, the answer to that question, "Who rules?" determines how we will live our lives. But the answer also determines who we will become as men and women.
For me, it boils down to this: "Who do you say that I am?" Jesus' question of Peter (Matthew 16:15) is one He also asks of all people. It is one all people must answer eventually.
If the answer is Jesus is Savior alone, He is only an expensive form of "fire insurance". If Jesus is Lord and King of our life, He becomes our purpose, our passion, and our desire. In this role, we then become defined by whom He says we are- falling right into His perfect plan for us- instead of a pale imitation created by following our own wishes. (And if the answer is "none of the above"- watch out! Hell is full of those with that answer!)
All the way back to the Garden of Eden, God's hand has been at work in creating man and determining his purpose. In His goodness, He has clearly communicated His desire for relationship with us as well as His desire to bless us. When Adam fell, taking all men with him, God himself provided the perfect sacrifice for sin, in sending His Son Jesus Christ. He is not some distant, detached, disinterested, deity. The Lord is a Good Father, one who loves His children, wants to save them, and has great plans for them! The Bible is full of these promises to us.
When God is the focus of our lives and when He reigns on the throne of our hearts, our desires become His, and we begin a lifelong process of becoming all He has intended. Only in this way, can we truly be fulfilled in life. He created each of us unique, and He alone knows what is in His heart for us. He will reveal his plan to us as we pursue Him. Of course, if we choose to live out our lives apart from Him, or only give Him a small part of it,we eventually end up in a trap of our own making. Life becomes frustrating or dull, mundane or fruitless, instead of vibrant, rich and hopeful. The choice is ours.
So, the question remains, "Who do you say that I am?" Everyday, I am challenged to live my life in accordance with my answer. The challenge is before you as well.