εἶπεν αὐτοῖς Ἰησοῦς Ἀμὴν ἀμὴν λέγω ὑμῖν, πρὶν Ἀβραὰμ γενέσθαι ἐγὼ εἰμί.
I've heard at least two rather strange assertions made about the grammar concerning this verse.
(a) That ἐγὼ εἰμί here functions not as a pronoun-verb of simple identification but as a proper name, of God.
(b) That ἐγὼ εἰμί here functions simultaneously as a pronoun-verb of simple identification and as a proper name of God.
IMHO either assertion is crazy, but both are ...