John 8:58

This was the third and last of Jesus’ solemn pronouncements in this discourse (cf. John 8:34; John 8:51). If Jesus had only wanted to claim that He existed before Abraham, He could have said, "I was." By saying, "I am," He was not just claiming preexistence but deity (cf. John 8:24; John 8:28; John 5:18; Exodus 3:14; Isaiah 41:4; Isaiah 43:13). [Note: See John A. Witmer, "Did Jesus Claim to Be God?" Bibliotheca Sacra 125:498 (April-June 1968):147-56.]

"It is eternity of being and not simply being that has lasted through several centuries that the expression indicates." [Note: Morris, p. 420.]

Jesus existed before Abraham came into being (Gr. genesthai).