Question: “Who was Nicodemus in the Bible?”
Answer: All that we know of Nicodemus in the Bible is from the Gospel of John. In John 3:1, he is described as a Pharisee. The Pharisees were a group of Jews who were fastidious in keeping the letter of the Law and often opposed Jesus throughout His ministry. Jesus often strongly denounced them for their legalism (see Matthew 23). Saul of Tarsus (who became the apostle Paul) was also a Pharisee (Philippians 3:5).
John 3:1 also describes Nicodemus as a leader of the Jews. According to John 7:50–51, Nicodemus was a member of the Sanhedrin, which was the ruling body of the Jews. Each city could have a Sanhedrin, which functioned as the “lower courts.” Under Roman authority in the time of Christ, the Jewish nation was allowed a measure of self-rule, and the Sanhedrin in Jerusalem was the final court of appeals for matters regarding Jewish law and religion. This was the body that ultimately condemned Jesus, yet they had to get Pilate to approve their sentence since the death penalty was beyond their jurisdiction under Roman law. It appears that Nicodemus was part of the Great Sanhedrin in Jerusalem.
John reports that Nicodemus came to speak with Jesus at night. Many have speculated that Nicodemus was afraid or ashamed to visit Jesus in broad daylight, so he made a nighttime visit. This may very well be the case, but the text does not give a reason for the timing of the visit. A number of other reasons are also possible. Nicodemus questioned Jesus. As a member of the Jewish ruling council, it would have been his responsibility to find out about any teachers or other public figures who might lead the people astray.
Source: Who was Nicodemus in the Bible?