Albert Barnes Commentary 1 Corinthians 12:13

"For in one Spirit were we all baptized into one body, whether Jews or Greeks, whether bond or free; and were all made to drink of one Spirit." — 1 Corinthians 12:13 (ASV)

For by one Spirit. This means that by the agency or operation of the same Spirit, the Holy Spirit, we have been united into one body. The idea here is the same as that presented above (1 Corinthians 12:7–11), by which all the endowments of Christians are traced to the same Spirit. Paul here says that the Spirit had so endowed them as to fit them to constitute one body, or to be united in one, and to perform the various duties that resulted from their union in the same Christian church. The idea that this was done by one and the same Spirit is maintained and often presented, so that the endowments conferred on them might be duly appreciated.

Are we all. Every member of the church, whatever his rank or talents may be, has received his endowments from the same Spirit.

Baptized into one body. Many suppose that there is a reference here to the ordinance of baptism by water. But the connection seems rather to require us to understand it as referring to the baptism of the Holy Spirit (Matthew 3:11), and if so, it means that by the agency of the Holy Spirit they had all been fitted, each to his appropriate place, to constitute the body of Christ—the church. If, however, it refers to the ordinance of baptism, as Bloomfield, Calvin, Doddridge, etc., suppose, then it means that by the very profession of religion made at baptism, and by there being only one baptism (Ephesians 4:5), they had all professedly become members of one and the same body. The former interpretation, however, seems to me to best suit the connection.

Whether we be Jews or Gentiles. There is no difference. All are on a level. Regarding the essential point, no distinction is made, whatever our former condition of life may have been.

Bond or free. It is evident that many who were slaves were converted to the Christian faith. Religion, however, regarded all as on a level and conferred no favors on the free that it did not on the slave. It was one of the blessed lessons of Christianity that it taught people that in the great matters pertaining to their eternal interests, they were on the same level. This doctrine would tend to secure, more than anything else, the proper treatment of those who were in bondage and those who were in humble ranks of life. At the same time, it would not diminish but would increase their real respect for their masters and for those who were above them, if they regarded them as fellow Christians and destined for the same heaven. (See Barnes on 1 Corinthians 7:22).

And have been all made to drink, etc. This probably refers to their partaking of the cup together in the Lord's Supper. The meaning is that by their drinking of the same cup commemorating the death of Christ, they had partaken of the same influences of the Holy Spirit, which descend alike on all who observe that ordinance in a proper manner. They had also shown that they belonged to the same body and were all united, and that however varied their graces and endowments might be, they all belonged to the same great family.