Now there was a man of the Pharisees named Nicodemus, a member of the Jewish ruling council. He came to Jesus at night and said, “Rabbi, we know you are a teacher who has come from God. For no one could perform the miraculous signs you are doing if God were not wih him.” John 3:1-2
(article from NIV Student Bible)
This meeting took place at night, in secret. Nicodemus was a ruling member of the Pharisees, a group that violently opposed Jesus. He likely risked danger by meeting with Jesus. Two other references to Nicodemus indicate that Jesus must have had a strong effect on him. He stood up for Jesus at the Jewish ruling council (John 7:50) and helped prepare Jesus’ body for burial (John 19:39).
Jesus’ meeting with the Samaritan woman (John 4:4-42) probably had some of the same tension, although it occured in daylight. Conversations between a Jew and a Samaritan, let alone between a religious teacher and an adulterer, were taboo.