6 but Christ as a Son over His own house, whose house we are if we hold fast the confidence and the rejoicing of the hope firm to the end.
if we hold fast [retain, occupy] the confidence [courage, boldness]
The “if” here constitutes a warning to remain firm in or confident in the assurance of what they believe. The word “confidence” conveys the idea of boldness. If believers hold to a bold faith in the face of the temptation to revert to previous belief, they will approach God with confidence (He 4:14; 10:23). Christians are to “retain” public boldness in their Christian walk.
The “if” is not a condition for becoming or remaining a Christian but is evidence for being a believer. Believers belong to Jesus’ house only on the ground of their faith. Those who lose their confidence and hope show evidence that they have failed to appreciate their privileges in Christ.
This phrase does not mean that we will be saved if we hold on until the end. That would mean we would save ourselves or keep ourselves in God’s kingdom. The idea from the argument of the book is that former Jews who became believers in Christ are to resist reverting back into Judaism. It is not right to revert to Moses when Jesus is superior to even someone as great as Moses. Our standing before God does not depend on our good works but on the work of Christ. It is solely by unadulterated grace.
The “if” clause in “if we hold fast the confidence” is conditional on the person’s will, maybe they will or maybe not hold fast to their confidence (third-class condition). This condition shows that all believers will not keep their confidence to the end.
The clause “if we hold fast” is followed by another hypothetical conditional clause in the next verse–”if you hear His voice.” Some believers may or may not response to God’s message (He 12:19-20, 24-25; 13:22). The argument in context is the faithfulness of Moses and Christ, with His being superior. None of us are as faithful as the Lord; that is not the argument of this passage.
It is important to note that the hypothetical idea here in 3:6 is explained further in 3:7-4:14. The conditional clause in this verse, “if we hold fast our confidence,” refers to the priestly worship of believers. By returning to the Mosaic system of sacrifices they would lose their confidence in the finished work of Christ. If they do not “hold fast” then they will no longer be able to participate in their priestly worship role provided by Christ (He 10:19-25). If they don’t hold fast then they are in danger of jettisoning their confidence (He 3:6, 14; 10:23–25, 35–39). The believer-priest function gives confidence. This forms the background to the passage that follows (He 3:7-4:14).
The context argues for the believer’s priestly activities (1 Pe 2:5). These people were addressed as “holy brethren” and “partakers of the heavenly calling.” Thus, to “hold fast” is an exhortation for Christians to grow in their faith. Their danger was failure to mature in what they believe (He 3:7-19). That failure will lead to temporal discipline from God. If they are faithful, then they will enter God’s “rest” (He 4:1-13).
We maintain stability in the Christian faith by continuing our confidence in the finished work of Christ unyieldingly.
We will remain loyal to Christ if we remain confident in our heavenly inheritance. That is why it is important to “consider Him” (He 3:1). We consider what He did for us in saving our souls eternally.
The argument of this verse is not that we are to keep ourselves saved. Neither does it show how we are to become Christians. The idea is that assurance is central to a maturing faith. The danger is that reversion will blunt the spiritual growth of anyone who does not “hold fast” to the content of what they believe (He 10:36). Failure to do this will bring temporal discipline on those who do not (He 3:7-19). If they do, they will enter God’s “rest” (He 4:1-13).
The exalted Son of God presides over a priestly apparatus which is operative throughout the Christian life. As long as believers hold firmly to their Christian profession, they will function within the benefits of Christ’s priestly apparatus. It is possible for a believer to step outside his own priestly role.