The unity (tēn henotēta). Late and rare word (from heis, one), in Aristotle and Plutarch, though in N.T. only here and Eph 4:13.
In the bond of peace (en tōi sundesmōi tēs eirēnēs). In Col 3:14 agapē (love) is the sundesmos (bond). But there is no peace without love (Eph 4:2).