Isaiah 43:11
Isaiah 43:1111I, yes I, am the LORD, and there is no Savior but Me.
"I — I am Jehovah, and besides me there is no saviour" (NWT). The Watchtower handles this verse by treating Jesus as the instrument through whom Jehovah saves, not as a saviour himself in the absolute sense. Old Testament judges are sometimes called "saviours" of Israel in a derivative sense; Jesus, on this reading, is the supreme but still derivative saviour. The verse is preserved without disturbing Watchtower Christology.
The verse rules out exactly the move the Watchtower needs. "Besides me there is no saviour" is absolute exclusivity, not a ranking. The Hebrew construction (en mibbal'aday moshia') leaves no room for "saviour-by-derivation." And then says of Jesus: "there is no salvation in anyone else, for there is no other name under heaven that has been given among men by which we must be saved." The two verses are structurally identical exclusivity claims, made of different referents — unless the referents are the same person. Pair with ("our great God and Saviour, Jesus Christ" — one article governing both nouns by the Granville Sharp rule), ("our God and Saviour Jesus Christ"), and ("a Saviour was born to you... who is Christ the Lord"). Either Jesus is Jehovah, or has been broken by the apostles' application of the Saviour title to Christ.