Both the one who makes men holy and those who are made holy are of the same family. So Jesus is not ashamed to call them brothers. Hebrews 2:11
Jesus is not ashamed to call us His brothers and sisters; despite the horrible way some people treated Him while He walked on the earth. He endured torment in order to make us holy, so that we might be welcomed into His heavenly kingdom without stain or blemish or the effects of sin. Jesus endured the cross because He loves us and wants us to live together as a family for eternity. It is the most joyous meaning of the Christmas season that God became one of us to redeem us from the curse of the law; but that is not our only joy.