“Both He who sanctifies and those who are sanctified are all from one Father; for which reason He is not ashamed to call them brethren, saying, ‘I will proclaim Thy name to My brethren, in the midst of the congregation I will sing Thy praise.’ And again, ‘I will put My trust in Him.’ And again, ‘Behold, I and the children whom God has given Me'” (Heb. 2:11-13).
Our holy Christ has made us holy; thus He can now call us His brothers.
From our own perspective and experience, it is difficult to think of ourselves as holy. Sin simply is too much a part of us in this fallen world. In thought and practice we are far from holy, but in Christ we are perfectly holy.
We may not always act holy, but because of our faith in Christ we are perfectly holy in God’s sight. Just as a child may not always act like his father, he is nonetheless still his son. We are holy in the sense that before God, the righteousness of Christ has been applied and imputed on our behalf through faith. We were made holy through His sacrifice and have become “those who are sanctified.”