Brothers and sisters: No one can say, "Jesus is Lord," except by the Holy Spirit.  There are different kinds of spiritual gifts but the same Spirit; there are different forms of service but the same Lord; there are different workings but the same God who produces all of them in everyone.  To each individual the manifestation of the Spirit is given for some benefit.  As a body is one though it has many parts, and all the parts of the body, though many, are one body, so also Christ.  For in one Spirit we were all baptized into one body, whether Jews or Greeks, slaves or free persons, and we were all given to drink of one Spirit.

Commentary

What Saint Paul is trying to impress upon us is that "different kinds of spiritual gifts" or "different forms of service" or "different workings" should not cause division.  We are a great diversity of people called to unity.  The physical body and its "many parts" is useful imagery for trying to understand the mystical body.  Saint Paul uses the word "different" three times in this short Reading.  We are all different – in fact, we are all unique.  No two people are exactly the same.  God produces spiritual gifts in each of us and calls us to service for the sake of the entire mystical body.  Saint Ambrose very directly taught: "Recall then that you have received the spiritual seal, the spirit of wisdom and understanding, the spirit of right judgment and courage, the spirit of knowledge and reverence, the spirit of holy fear in God's Presence. Guard what you have received. God the Father has marked you with His sign; Christ the Lord has confirmed you and has placed His pledge, the Spirit, in your hearts" (De mysteriis).  The need to guard anything suggests that it could escape or be taken away.  Our Savior tells us that whosoever shall drink of the water which He gives, it shall become a well of water springing up unto everlasting life (cf. John 4:14).  Saint Paul tells us in the Reading that this drink is the Spirit.  Once again, Saint Ambrose continues with that thought and adds: "This well is clearly the grace of the Spirit, a stream proceeding from the living Fount. The Holy Spirit, then, is also the Fount of eternal life" (ibid.).