I attempt to find the main causes of the serious disunity in the Presbyterian Church in Korea
(PCK), which started as one church but is now divided into more than 100 denominations, as
well as a solution to promote the unity of the PCK. This attempt starts with an exegesis of
Ephesians, with special reference to Ephesians 4:1–16, to understand the biblical principle on
this matter. This article draws on a mature ecclesiology and a mature sense of unity as key
concepts. After that, the history of the PCK disunity is briefly described, dealing with four
major schisms. Based on this historical investigation, the disunity in the PCK is assessed. In
addition, the weak sense of unity and weak ecclesiology of the PCK, which played a role in its
disunity, are discussed in view of the confessions of faith, the ministry of the word and the
Lord’s Supper, and ecumenical efforts in relation to national and international ecumenical
organisations. Lastly, contributory suggestions based on the mature sense of unity are offered
to the PCK in particular and the Reformed family and all Christian churches in general.
INTRADISCIPLINARY AND/OR INTERDISCIPLINARY IMPLICATIONS : In my ecumenical Reformed
intradisciplinary assessment of unity and catholicity in the PCK, which started as one church
but is now divided into more than 100 denominations, I identify the main causes of serious
disunity in the PCK, namely a weak sense of unity, immaturity and secularisation.