In every way, God is greater than man. A man would have to be a thief to claim equality with God. Yet, Christ thought it not robbery to be equal with God.
John wondered at the thought that there would be a time in the future when a group identifying as Christian would put others to death for having faith in Christ.
A martyr is one who is killed for his faith. Only two individuals are specifically named as martyrs in scripture: Stephen and Antipas.
