Rabbi, meaning teacher, was, and is, a dignified title given by Jews to doctors of the religious law and distinguished teachers. In the New Testament, it was most often recorded when used by His disciples for Jesus Christ.
"She turned and said to Him in Hebrew, "Rabboni!" which means Teacher"
John The Baptist was addressed as Rabbi by his disciples, even as John humbly explained to them that he was to prepare the way for a greater Rabbi:
"And they came to John, and said to him, "Rabbi, He Who was with you beyond the Jordan, to Whom you bore witness, here He is, baptizing [see Baptism], and all are going to Him."
John answered, "No one can receive anything except what is given him from heaven. You yourselves bear me witness, that I said, I am not the Christ, but I have been sent before Him. He who has the bride is the bridegroom; the friend of the bridegroom, who stands and hears Him, rejoices greatly at the bridegroom's voice; therefore this joy of mine is now full. He must increase, but I must decrease." (John 3:26-30 RSV)
Jesus Christ was addressed as Rabbi:
"Jesus turned, and saw them following, and said to them, "What do you seek?" And they said to Him, "Rabbi," which means Teacher, "where are You staying?" (John 1:38 RSV)
"Nathanael answered Him, "Rabbi, You are the Son of God! You are the King of Israel!" (John 1:49 RSV)
"Now there was a man of the Pharisees, named Nicodemus, a ruler of the Jews. This man came to Jesus by night and said to Him, "Rabbi, we know that You are a teacher come from God; for no one can do these signs that You do, unless God is with him." (John 3:1-2 RSV)
"So when the people saw that Jesus was not there, nor His disciples, they themselves got into the boats and went to Capernaum, seeking Jesus. When they found Him on the other side of the sea, they said to Him, "Rabbi, when did You come here?" (John 6:24-25 RSV)
Mary of Magdala, the first human to see Jesus Christ after His resurrection, addressed Him as Rabboni, which like Rabbi, means teacher:
"Jesus said to her, "Woman, why are you weeping? Whom do you seek?"
"Supposing Him to be the gardener, she said to Him, "Sir, if You have carried him away, tell me where You have laid Him, and I will take Him away."
"Jesus said to her, "Mary."
"She turned and said to Him in Hebrew, "Rabboni!" which means Teacher."
"Jesus said to her, "Do not hold Me, for I have not yet ascended to the Father; but go to My brethren and say to them, I am ascending to My Father and your Father, to My God and your God." (John 20:15-17 RSV)
Fact Finder: Because of the amount of hypocrisy among the Scribes and Pharisees of that time (see Hypocrites), what did Jesus Christ, Who was a Jew (Luke 4:16, John 4:9-10), teach His disciples about the use of the term Rabbi?