one Lord, one faith, one baptism, (ESV)
Paul continues his thoughts on unity. As he talks to these Ephesians he emphasizes that there is one Lord. In the ancient city of Ephesus there was a idol of a god on every street corner. They worshiped all kinds of gods. All of them were false gods. As Paul is emphasizing the unity that Christ brings to both Jew and Gentile he reminds them that there is only one Lord. This would have been a major cultural change for the Ephesians. But a necessary one.
One faith. How many times have you heard someone say, "As long as you have faith, that's all that matters." Faith in what? Faith in whom? Scripture makes clear that there is only one legitimate faith. The Epistle of Jude speaks to this point:
 Beloved, although I was very eager to write to you about our common salvation, I found it necessary to write appealing to you to contend for the faith that was once for all delivered to the saints. (ESV)
Notice how he says, "our common salvation." Maybe you believe in some kind of religion. Maybe you have a believe in some vague sort of God. There is only one faith. That faith has a object. Jesus Christ. There is only one faith. Faith that is not placed in Jesus Christ is not faith at all. It is folly. Christian, it is essential that when you share your "faith" that you remind people that faith is more than a generic belief, it has Christ alone as it's object.
One Baptism. Water baptism is a believers first act of obedience. All throughout the Book of Acts the repeated phrase is "repent and be baptized." Baptism follows repentance. All of us are called to the same act of obedience. What a beautiful time it is when a church baptizes new believers. They are publicly identifying that they have been washed of their sins. One baptism.
Think of what you have in common with believers all over the world. One Lord. One faith. One baptism.