It is not possible to be a Christian without child-like faith to first enable us to believe that an invisible entity is the Son of God and then believe in and love Him so strongly that he agrees to send His Holy Spirit to us to make us truly "born again." It is a child-like faith that Jesus was referring to in this often misinterpreted verse:
Matthew 19:14 (Contemporary English Version)
But Jesus said, "Let the children come to me, and don't try to stop them! People who are like these children belong to God's kingdom."
Jesus spoke often of the crucial importance of faith as these verses show:
Acts 26:17-18 (Contemporary English Version)
17The Lord also said, "I will protect you from the Jews and from the Gentiles that I am sending you to. 18 I want you to open their eyes, so that they will turn from darkness to light and from the power of Satan to God. Then their sins will be forgiven, and by faith in me they will become part of God's holy people."