The Greek verb aletheuoo (ἀληθεύω) means to speak the truth, to be truthful, to deal honestly. It is related to aletheia (G225, truth) and alethes (G227, true). The verb captures not merely stating accurate facts but living consistently in truth.
Paul uses aletheuoo in Galatians 4:16 — 'Have I now become your enemy by telling you the truth (aletheuoon)?' — and in Ephesians 4:15 in the celebrated phrase 'speaking the truth in love (aletheuontes en agape).' The Ephesians passage reveals the New Testament's distinctive combination: truth is never to be weaponized but always embedded in love, as the body grows toward Christ who is both the Way and the Truth. Truth-speaking that lacks love becomes harshness; love without truth becomes flattery.