homologeō

At its heart this word means to say the same thing as someone else out loud and on the record. In the New Testament that most often means openly owning Jesus in front of other people: naming him as Lord, as the Son of God, or as the one who has come in human flesh, and standing by that claim where others can hear it. It is the exact opposite of denying (ἀρνέομαι) him, and the two are constantly set against each other.

This is public and costly, not a private opinion. To confess Christ before a hostile crowd, a synagogue, or a Roman court was to commit oneself in a way that others could hold against you, and it could get a person thrown out or put on trial. That binding, on-the-record quality is why the same verb covers both a heartfelt profession of faith and a formal declaration made before witnesses.

Scholars disagree about how fixed these confessions already were. Some hear ready-made statements of faith behind texts like Romans 10:9; others hear a looser, living language of loyalty that had not yet hardened into a set creed. Either way the act is the same: publicly aligning oneself with Jesus and refusing to take it back.

This is the plainer, everyday side of the word: to grant that something is true. Sometimes that means acknowledging a fact or a belief that others hold, as when one group affirms that resurrection, angels, and spirits are real. Sometimes it means owning something true about oneself, whether admitting one's actual situation or confessing one's sins to God.

What ties these uses together is honesty put into words. To acknowledge that one is only a stranger passing through, or to confess a wrong, is to stop pretending otherwise and say plainly what is the case.

Here the word means to promise: to bind oneself by a stated pledge to do something. In the wider Greek world this was the ordinary language of legally binding agreements, the word that opened countless contracts, and it kept that weight of a firm, public commitment. When Herod promises with an oath to give the girl whatever she asks, and when God is said to have promised a homeland to Abraham, the word marks a pledge the speaker is bound to keep.

In this sense the word turns toward worship: to praise God and give him thanks out loud, openly acknowledging who he is. This use grows out of the Old Testament language of thanksgiving (ידה), where praising God and confessing his name are one and the same act of speaking his worth. The letter to the Hebrews calls such praise the fruit of lips that acknowledge his name, an offering made with words.