“All for One and One for All.” It’s this expressive phrase of unity that Paul is addressing in these verses. The origin of this phrase does not come from the French language or the Three Musketeers book, it was originally found in Latin and from Shakespeare. The original order is “One for All and All for One.” And it’s this word order that fits our text perfectly.
Here Paul is discussing how both Jew and Gentile can be brought together in Christ. This was once a mystery but now has been revealed in the Gospel.
Christ is the One and we are the All. One died for all and All and for the One. Jew or gentile, black or white, male or female. Christ died once for all and all can be one in Christ, hence, One for All and All For One.