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 with him." (John 3:1-2)
Modern critics of the Bible start with the assumption that miracles are impossible. Such a huge assumption, based on a materialistic worldview (materialism not as in money, but as in matter is all that exists) distorts their view of scripture and their ability to treat it fairly. But notice that Nicodemus, who was aligned with Jesus' fiercest opponents, accepted the miracles as real. He had every motivation to not believe in Jesus, for Jesus was a threat to his power, but he was honest enough to accept the reality and the implication of Jesus' miraculous power. This is a great testimony to the veracity of Jesus' life.