The chapter begins with a warning: we must pay closer attention to what we have heard so that we do not drift away like a boat slipping from its mooring. If the message spoken through angels was binding and every transgression received its penalty, how shall we escape if we neglect so great a salvation? That salvation was first announced by the Lord, confirmed by those who heard him and backed by God with signs, wonders, miracles and gifts of the Holy Spirit.
The author then cites Psalm 8: human beings were made a little lower than the angels, crowned with glory and honor, with everything under their feet. We do not yet see everything subjected to humanity, but we do see Jesus, made for a little while lower than the angels because of the suffering of death and now crowned with glory and honor, because by the grace of God he tasted death for everyone.
It was fitting that God, in bringing many sons to glory, should make the founder of their salvation perfect through suffering. The one who sanctifies and those who are sanctified all have one source, so Jesus is not ashamed to call them brothers, and the author quotes the Psalms and Isaiah to show it. Since the children share in flesh and blood, he too shared in the same, so that through death he might destroy the one who had the power of death, the devil, and free those who through fear of death were subject to lifelong slavery.
For that reason he had to be made like his brothers in every respect, so that he might become a merciful and faithful high priest in the service of God and make propitiation for the sins of the people. And because he himself suffered when tempted, he is able to help those who are tempted.