In this verse, Paul sums up our purpose here on earth as Christians. The outward sign of our inward faith in Christ is love. When we love others we are showing the world who God is because God is love (1Jn 4:8). All that matters, all that makes a difference, all that counts is living a life of faith through love.
Matthew 22:36-40 “Teacher, which is the greatest commandment in the Law?” Jesus replied: “ ‘Love the Lord your God with all your heart and with all your soul and with all your mind.’ This is the first and greatest commandment. And the second is like it: ‘Love your neighbor as yourself.’ All the Law and the Prophets hang on these two commandments.”
John 13:34-35 “A new command I give you: Love one another. As I have loved you, so you must love one another. By this everyone will know that you are my disciples, if you love one another.”
We try to make it so hard and confusing but when it comes down to it, like the song says, all you really need is love!