Revelation 2:23
Revelation 2:2323Then I will strike her children dead, and all the churches will know that I am the One who searches minds and hearts, and I will repay each of you according to your deeds.
JWs treat this as Jesus speaking to the congregations as Jehovah's appointed king — searching hearts in his judicial role. They do not connect the heart-searching language to and the exclusivity of that divine attribute.
Verse 18 names the speaker as "the Son of God". In verse 23 the Son of God says, "I am the one who searches the innermost thoughts and hearts, and I will give to each one of you according to your deeds". That is verbatim Jehovah-language from — "I, Jehovah, am searching the heart, examining the innermost thoughts, to give to each one according to his ways". Heart-searching is an exclusive divine attribute; the Son of God claims it for himself in identical terms. The Son shares the very prerogative the Watchtower says belongs to Jehovah alone.
The Greek nephros literally means "kidneys" — in ancient Hebrew and Greek thought, the kidneys were the seat of the deepest emotions. The NWT 2013 renders it "innermost thoughts" in the main text with "kidneys" relegated to a footnote. The translation choice is not itself the doctrinal issue; the doctrinal issue is that the Watchtower uses 's heart-searching to argue for Jehovah's unique deity, then reads — the Son using identical vocabulary — without noting that the Son has just claimed the same attribute.