1 Corinthians 12:13 (ESV)

13 For in one Spirit we were all baptized into one body Jews or Greeks, slaves or free and all were made to drink of one Spirit.

However different the members of the church may be, they have all been incorporated into one body by one Spirit.

Paul mixes two metaphors here, comparing the church to both a body and a river (into which a believer is baptized). Thus he reminds the Corinthians of their baptism, by which they were visibly joined to Christ and to each other. Again (as in the first three verses of the chapter) Paul has in mind not the Spirit’s work of giving gifts to God’s people, but rather his work of imparting life to them through faith. This is the principal work of the Spirit, of which baptism is a sign. 

To drink of the Spirit is to enjoy of his fullness. Jesus called the Spirit living water (John 4:10; John 7:38–39). Elsewhere Paul draws a contrast between getting drunk with wine and being filled with the Spirit (Ephesians 5:18).