dikaiōma

This is what the word means most of the time in the New Testament. A rule of this kind is not merely something on the books; it states what is right, so keeping it is doing right. Luke pairs it with the ordinary word for a command (ἐντολή) when he describes Zechariah and Elizabeth walking blamelessly in everything the Lord had laid down.

The rules in view cover a wide range:

• what God has spelled out for his people to live by
• what the law as a whole rightly demands of anyone, whether or not they were born inside it
• God's settled decision about what a given course of conduct deserves
• the regulations for worship and outward purity that governed the older sanctuary

The word is built from the verb meaning to declare or set right (δικαιόω), and its ending points to a finished product rather than an ongoing action. A rule of this sort is what rightness looks like once it has been put into words. That is why Paul can speak of the law's demand being "fulfilled" in people who live by the Spirit rather than simply obeyed by them: the requirement describes right living, and the Spirit produces it.

The same word that names the rule can name the deed that answers it. That is not clever wordplay but the natural reach of a word for a thing made right: what is laid down as right and what is carried out as right are two ends of one idea.

The New Testament keeps this use for weighty acts. Paul uses it for the single obedient act of Christ that undoes what Adam's one failure did. Revelation uses it twice, once for the deeds of God that the nations will finally acknowledge, and once for the deeds of God's people, pictured as the bright, clean linen the bride is dressed in. In each case the act is public and visible, something that has come out into the open.

The plural in Revelation repays attention. The bride's dress is not one achievement but many acts, and it is "given" to her, so the passage holds grace and conduct together without explaining how they fit. Outside the Bible, Greek writers used this word for a claim or a right that a person could actually make good on, which points the same direction: a thing realized, not a thing merely felt.

Paul sets this word directly against the word for a sentence of condemnation. The picture is a courtroom: one ruling sends the accused down, the other clears them. Here the word names neither a rule nor a deed but the decision itself, the outcome handed down from the bench.

This use appears once in the New Testament, in the middle of Paul's comparison between Adam and Christ, where he is stacking courtroom language on both sides of the ledger. It still fits the shape of the word, a thing that has been made right, only here by a ruling rather than by a rule or an act. The closely related word for the act of setting someone right (δικαίωσις) turns up two verses later, which shows how tightly Paul is working this family of words in one paragraph.