In fellowship group last night we paused to consider the significance of these verses in Hebrews 7:
For it was fitting that we should have such a high priest, holy, blameless, undefiled, separated from sinners, and exalted above the heavens. Unlike the other high priests, he has no need to offer sacrifices day after day, first for his own sins, and then for those of the people; this he did once for all when he offered himself. For the law appoints as high priests those who are subject to weakness, but the word of the oath, which came later than the law, appoints a Son who has been made perfect for ever.
One of the things that struck me was what the author makes of the (sinless) life of obedience of the Lord. It’s part of what enables Him to fulfil His office as the unique Messianic high priest ‘according to the order of Melchizedek’.
Unless He had lived such a life, he’d be in the same compromised situation as the Levitical priests — having to offer a sacrifice for His own sin before being able to make atonement for the people, and thus remaining embroiled in the endless succession of sacrifices.
The ‘active obedience’ of Christ’ incarnate life — the Son’s perfection in identifying with and suffering for humanity (cf. Heb 2.5-18) — underwrites the effectiveness of His ‘passive obedience’ in securing our forgiveness.
As a result, Christ’s life of obedience is meant to bolster our confidence in the decisive, Once-for-All-ness of His achievement!