Scripture portrays great richness and variety in the use of the term. There is the unity of the believer with his Lord, and there is the union manifested in the body of Christ, the Church, which rests eventually on a deeper unity of believers in “one Lord, one faith, one baptism.” Unity with Christ is illustrated in many ways: that of husband and wife, or the stones and the building. The classic analogy is the vine and the branches (cf. John 15 passim). Apart from such unity the follower of Christ can “do nothing.” The unity is his life and the ground of his action.

Terminology

The Hebrew word of the Old Testament is ֭יַחַד (unitedness) and the Greek of the New Testament is ἑνότης, G1942, (oneness), the meaning being quite evident in the root of ἑνότης, G1942, from εἱ̂ς, ἑνός which means simply “one.”

Usage

Used in the Old Testament in the sense of togetherness of persons (Gen.13.6 and Ps 133:1), fellowship (Judg.19.6), and praise (Ps.34.3). Isa.11.6-Isa.11.7 tells of a future time when there will be a togetherness among animals.

The New Testament word speaks of the unity of faith that binds together the people of God (Eph.4.13).

Also Sirach 25:1 the King James Version for homonoia "concord" (so the Revised Version.

Paul and Unity

Paul took special interest in the unity within the body of believers and he did not argue for the invisible but for the visible body. He recognized unity in diversity and diversity in unity and he amplified this approach (1 Cor 12) with the appeal to love as the unifying bond (ch. 13).

Paul looked upon unity as reality already in existence, but also as a reality yet to be attained (Eph 4). Appealing as he did in his great hymn of love (1 Cor 13) he writes, “forbearing one another in love,” one is then “eager to maintain the unity of the Spirit.” There exists this unity already, but it is the unity of the Spirit, which fact relates to his treatment of diversity in unity (12). One should expect from this “one Lord, one faith, one baptism” (cf. Eph 4:2, 3, 5).

That the real unity here described is not manifest in the Church nor among the most ardent followers of Christ is quite clear; Paul wrote of unity as something yet to be attained. There are varieties of gifts and offices for the building up of the body of Christ “until we all attain to the unity of the faith and of the knowledge of the Son of God.” Then will come “mature manhood...the fulness of Christ” (4:13).