E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Either to stick to or to part from. A man shall cleave to his wife (Matt. xix. 5). As one that cleaveth wood (Psalm cxli. 7). The former is the Anglo-Saxon clíf-an, to stick to, and the latter is cleof-an, to split.