65 Grk “to the Jews.” In NT usage the term Ἰουδαῖοι (Ioudaioi) may refer to the entire Jewish people, the residents of Jerusalem and surrounding territory (i.e., “Judeans”), the authorities in Jerusalem, or merely those who were hostile to Jesus. (For further information see R. G. Bratcher, “ ‘The Jews’ in the Gospel of John,” 26 [1975]: 401–9; also Ἰουδαῖος 2.e.) Here the phrase refers to the Jewish people in Jerusalem who had been listening to Jesus’ teaching in the temple and had believed his claim to be the Messiah, hence, “those Judeans who had believed him.” The term “Judeans” is preferred here to the more general “people” because the debate concerns descent from Abraham (v. 33).
66 Grk “If you continue in my word.”
67 Or “truly.”

In other versions

So Jesus said to the Jews who had believed him, “If you abide in my word, you are truly my disciples,

To the Jews who had believed him, Jesus said, “If you hold to my teaching, you are really my disciples.

Then Jesus said to the Jews who had believed him, “If you continue in my word, you really are my disciples.

Jesus said to the people who believed in him, “You are truly my disciples if you remain faithful to my teachings.

Then Jesus said to those Jews who had believed him, “If you continue in my word you are truly my disciples,

Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed;

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