For just as the body is one and has many members, and all the members of the body, though many, are one body, so it is with Christ. For in the one Spirit we were all baptized into one body—Jews or Greeks, slaves or free—and we were all made to drink of one Spirit. Indeed, the body does not consist of one member but of many.
Paul uses the metaphor of the body to emphasize the unity of the believers in Christ despite the largest cultural differences that would have existed within his audience in Corinth: Jews and Greeks (the non-Jews), slaves and freemen. The appeal to all classes and races would have been radical at the time. Judaism is not an evangelical religion. Other belief systems were spread by conquest and enslavement, not by conversion. For Paul to include Jews and Greeks broadens his message to something more than just an obscure Jewish sect (there were many of those already.) And for Paul to include slaves and free people shows that his message was not based on conquest, but on free will.
What does this have to do with our spiritual gifts? Paul makes it clear that everyone, everyone is part of the body. Therefore we cannot be a whole and complete body unless we include all of our parts. We cannot stand without legs, nor can the Church stand when it is divided by generation, race, culture, political beliefs, or any other name for the dismembering of the body. We each have spiritual gifts, but we are unable to effectively fulfill God’s purpose when we attempt, through action or inaction, to exclude others. We’re going into battle with a blindfold.