Q: Why are we called the Children of Christ?
A: We are called the Children of Christ because we are direct decendents of his Kingdom. In His Word He says... in - Romans 8:17:
"And if we are [His] children, then we are [His] heirs also: heirs of God and fellow heirs with Christ [sharing His inheritance with Him]; only we must share His suffering if we are to share His glory."
A2:Also it says in... Ephesians 1:5
"For He foreordained us (destined us, planned in love for us) to be adopted (revealed) as His own children through Jesus Christ, in accordance with the purpose of His will [(Marvin Vincent, Word Studies in the New Testament) because it pleased Him and was His kind intent]--