If we desire to enter into the kingdom of God, we must come as little children  -  Matthew 18:3

And said, Verily I say unto you, Except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven.

Jesus said that to enter into the kingdom of heaven an individual must come to Him as a little child. This does not mean that we must go back into time, but that we abandon our pride and take the position of a little child, and acknowledge our sinfulness and unworthiness and receive Jesus Christ as our Saviour.