Isaiah 45:23
Isaiah 45:2323By Myself I have sworn; truth has gone out from My mouth, a word that will not be revoked: Every knee will bow before Me, every tongue will swear allegiance.
JWs cite freely as a Jehovah text — every knee bowing and every tongue swearing belongs to Jehovah alone, the Almighty God who has sworn by himself. They use it to underline the exclusive worship of Jehovah and the impossibility of divided allegiance. The conversation becomes uncomfortable only when is brought into the picture, because Paul applies this same Jehovah-only homage to Jesus Christ — at which point JWs typically retreat to "Jesus is the agent through whom this honour reaches Jehovah," reframing the verse as pointing past Jesus rather than to him.
is one of the most jealous monotheistic texts in Scripture. Jehovah swears by himself ("I have sworn by myself") that every knee will bow to him and every tongue swear allegiance to him. In its original context this honour cannot be shared with any creature — verses 21-22 explicitly deny that there is "any other God besides me." Paul then takes precisely this passage and applies it to Jesus at : "every knee should bow… and every tongue confess that Jesus Christ is Lord, to the glory of God the Father." The vocabulary is identical to the LXX of . Paul cannot be giving to Jesus what Isaiah's Jehovah refuses to share with any creature unless Jesus is included within the identity of Jehovah. The same Pauline move appears at , where Paul again quotes in a context that drives toward Christ's lordship over the dead and the living. ("I am Jehovah, who made everything… by myself") and form a matched pair the apostles repeatedly load onto Jesus.
The NWT renders itself with "Jehovah" — the verse is OT Hebrew and contains the Tetragrammaton, so this is unremarkable. The divergence appears at the cross-reference: when Paul quotes at , the NWT's stated rule is that kyrios in NT quotations of YHWH passages should be rendered "Jehovah." But doing so at would yield "Jesus Christ is Jehovah," so the NWT retains "Lord." At the parallel quotation in — where the immediate referent is less explicitly Christ — the NWT does insert "Jehovah." Same OT source, two different treatments, divided along whether the result would identify Jesus as YHWH. The master divergence table flags as a "High" doorstep-utility verse for exactly this reason; is the Old Testament half of the same case.