From heteros ('different') and zugos ('yoke'). Heterozugeo means to be yoked together with one of a different kind β a mismatch that hinders effective work and strains both parties.
2 Corinthians 6:14's command 'Be ye not unequally yoked together with unbelievers' uses this vivid agricultural image. Ancient farmers knew that yoking an ox with a donkey was futile β their different strengths, gaits, and dispositions made coordinated work impossible. Paul applies this to marriage (as primary context) and to all covenantal partnerships where spiritual incompatibility would sabotage the relationship's purpose. The principle is not social separation but covenantal wisdom: the deepest commitments of life β marriage, business partnerships, spiritual alliances β require shared foundation in Christ. The yoke of Christ (Matthew 11:29β30) is only rightly worn with those who share it.