Sexual differentiation is explained in the creation narratives as part of God's design for humanity. It is good; and it is necessary for the continuation of the race. It is expressed in OT narratives in polygamy (1 Kgs. 11: 1–3), concubinage (Gen. 16: 1–4), and Levirate marriage (Deut. 25: 5–10). Divorce was permissible (Deut. 24: 1–4); homosexual acts were not (Lev. 18: 22). The emphasis throughout was on the production of future generations and the birth of children showed the divine favour (Ps. 127: 3–5). But the Song of Songs is a witness to the worth of erotic love in itself without reference to marriage.
The NT teaching is conditioned by an expectation of the possible end of the world and the consummation of the Kingdom, which lent a negative view on human, temporal relationships which could distract from the imperatives of expectation (1 Cor. 7: 31). However, the Gnostic view that the material world is evil and the body and its passions to be denied is firmly rejected (Col. 2: 20–23; 1 Tim. 5: 23; Heb. 13: 4), but Paul is aware that passions do not have unrestricted moral licence (Rom. 1: 24–7).