Jeremiah 17:10
Jeremiah 17:1010I, the LORD, search the heart; I examine the mind to reward a man according to his way, by what his deeds deserve.
Read straightforwardly as an attribute of Jehovah: only Jehovah can examine the heart and the innermost thoughts of every person. The Watchtower has no quarrel with this verse in itself — its difficulty surfaces only when the same heart-reading is attributed to Jesus.
is the matching key for : "Jesus, knowing in his spirit that they were reasoning this way among themselves..." The scribes thought their objection privately; Jesus answered it as if he had heard it. Same chapter, same passage, Jesus also says he forgives sins — which the scribes correctly identify as a divine prerogative ("Who can forgive sins except one, God?" — ). Pair with the gospel episodes where Jesus reads hearts (; ; ) and the conclusion writes itself: the heart-reader of has appeared in person, and the scribes did not have to revise their theology — they had to revise their list of who counts as Jehovah.