James 5:12

πρὸ πάντων marks the importance of what follows.

μὴ ὀμνύετε κ.τ.λ. This emphatic rule is founded on the Lord’s words, recorded by St Matthew only, Matthew 5:33 ff. μὴ ὀμόσαι ὅλως κ.τ.λ. Comp. Matthew 23:16-22. The only oath enjoined in the Mosaic code is that by which an accused person cleared himself from the charge, Exodus 22:11; Leviticus 5:1; Leviticus 6:3; Numbers 5:19-22. Comp. Deuteronomy 6:13; Deuteronomy 10:20; Psalms 63:11. But such was the sanctity attached to an oath that it could not be demanded on a trivial accusation; a denial was sufficient (τὸ ναὶ ναὶ καὶ τὸ οὐ οὐ), or the word amen or σὺ εἶπας (see Matthew 26:63-64) constituted an oath. By a curious inconsistency an oath taken by heaven, earth, Jerusalem or any other creature came to be regarded as invalid (Mishnah, Shebuoth IV. 13, as cited by Dr Ginsburg, Kitto’s Encyc. under ‘Oath’), compare our Lord’s words, Matthew 23:16-22.

So great was the fear of offending by a false oath that pious Jews before the time of Christ discountenanced swearing altogether: Sir 23:9-11 ὅρκῳ μὴ ἐθίσῃς τὸ στόμα σου, καὶ ὀνομασίᾳ τοῦ ἁγίου μὴ συνεθισθῇς … ἀνὴρ πολύορκος πλησθήσεται�, καὶ οὐκ�, κ.τ.λ. The Pharisees avoided oaths as much as possible, the Essenes entirely,—a rule which even Herod was obliged to recognise by exempting the Essenes from the oath of allegiance, Joseph. Ant. xv. 10. 4. For the whole subject see Kitto’s Encycl., under ‘Oath.’

ἤτω. For this rare form see Veitch sub voc. εἰμί. In Plat. Rep. 361 ἔστω is now read or ἴτω.

The construction with the accusative is more classical than the idiom used Matthew 5:34-35 ἐν τῷ οὐρανῷ … ἐν τῇ γῇ.