John 4:25-30 — The woman saith unto Him, I know that Messias cometh, which is called Christ: when He is come, He will tell us all things.
Jesus saith unto her, I that speak unto thee am He.
And upon this came his disciples, and marvelled that He talked with the woman: yet no man said, What seekest thou? or, Why talkest Thou with her?
The woman then left her waterpot, and went her way into the city, and saith to the men,
Come, see a man, which told me all things that ever I did: is not this the Christ?
Then they went out of the city, and came unto Him.
The woman had her sin and false worship exposed. She longed for the Messiah who would make it all clear to her.
I know the Messiah comes — in response to Christ's words, "the hour comes."
The woman expressed her desire for the Messiah and Jesus immediately responded, in essence, "You have Him."
I that speak unto thee am He = literally, "I AM that speaketh unto thee." I AM is a title of Jehovah. Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I AM (John 8:58).
Jesus avoided telling the Jews He was the Messiah. Then came the Jews round about Him, and said unto Him, How long dost Thou make us to doubt? If Thou be the Christ, tell us plainly (John 10:24). They didn't understand what and who the Messiah was, but He told the Samaritans.
The disciples wondered that Jesus would talk with a Samaritan, but they knew better than to ask Him about it.
As a rule, Rabbis didn't talk with women (and certainly not ones with this woman's reputation) and Jews didn't talk with Samaritans.
left her waterpot — left her errand undone. Her spiritual thirst was satisfied. She forgot about her physical thirst.
She went from an adulteress to a witness in minutes.
They … came unto Him — the verb suggests that more and more people kept on coming.