The unity (την ενοτητα). Late and rare word (from εις, one), in Aristotle and Plutarch, though in N.T. only here and verse Ephesians 4:13.

In the bond of peace (εν τω συνδεσμω της ειρηνης). In Colossians 3:14 αγαπη (love) is the συνδεσμος (bond). But there is no peace without love (verse Ephesians 4:2).