The Greek verb miseo means to hate or to detest. It is used both of intense personal hostility and, in Semitic idiom, of relative preference — to 'hate' can mean to prefer one thing so much that the alternative seems like hatred by comparison (Luke 14:26; 'hate' father and mother means love Christ incomparably more). The word is used of the world's hatred of believers and of God's hatred of wickedness.
Miseo establishes a clear moral and eschatological divide in John's writings. The world (kosmos) hates believers because it hated Christ first (John 15:18–19). This is not incidental — it is the inevitable result of light confronting darkness. Believers are warned not to 'hate' their brothers (1 John 2:9–11; 3:15), for hatred is spiritual murder. Yet miseo also describes the believer's appropriate posture toward sin: 'hate what is evil' (Romans 12:9).