Hebrews 3:1
1Therefore, holy brothers, partakers of a heavenly calling, consider the Apostle and High Priest of our confession: Jesus,
Therefore—on the ground of the Son who shared flesh and blood and is a merciful, faithful high priest—holy brothers who share a heavenly calling must consider Jesus. Wesley: God calls from heaven, and to heaven, by the gospel. The Apostle is the messenger who pleads God's cause with us; the High Priest pleads our cause with God; both are in the one word Mediator. He bears together, and far more eminently, the offices Moses and Aaron bore severally. Of our profession: the religion we confess.
The call is earnest and heavenly; the response is to fix the mind on Jesus, not on lesser mediators. Shared christology here: he is truly apostle and high priest of the confession. Considering him is not a bare glance; it is the living attention grace enables and faith owes.
Calvin: he concludes the preceding doctrine with a necessary exhortation—consider what sort of being and how great Christ is. The word consider intimates that singular attention is required; he cannot be disregarded with impunity. God favored them with no common grace when he called them into his kingdom; it remains that they fix their eyes on Christ as leader. Confession here stands for the faith professed—vain unless Christ is its object.
Holy brothers and heavenly calling name those God has set apart; the command is still to attend diligently to the Son. Jesus alone is apostle and high priest of our confession. The same Lord who called must be considered, or the profession is empty.