6:6 if they then fall away. There is a kind of falling away that is irreversible (1 John 5:16). Christian salvation is final (10:4), and the decision to reject it, if made at a certain level, cannot be reversed. According to 1 John 2:19, anyone who makes such a decision was not really a member of the household of faith, although they may have seemed to be. Judas Iscariot is the clearest example of someone who participated in the coming of the kingdom, but did not enter it (Matt. 26:47–49; cf. Matt. 7:21–23). This warning is not to encourage speculation about whether others are irretrievably lost, but urges us to cling closely to the Savior ourselves. See “The Unpardonable Sin” at Mark 3:29.

crucifying once again the Son of God. By renouncing their faith in Christ they declare that Christ’s cross is not a holy sacrifice for others’ sins, but the deserved execution of a guilty criminal (10:29). Such apostates have returned to a point where the Cross does nothing but condemn them as accomplices in murder (Acts 18:5, 6).

There is an analogy between the once-for-all character of Christ’s sacrifice for sin and the believer’s symbolic participation in that crucifixion through baptism (v. 4 note). Christ’s sacrificial death cannot be repeated. In the same way, the believer’s participation in His death, sealed by baptism (Rom. 6:3, 4; Col. 2:12), cannot be withdrawn and then repeated.

contempt. The apostasy described in ch. 6 is not a matter of private, internal doubt. It is the forceful, complete, and public rejection of a faith once confessed. As such, it has bad effects for others as well as for the apostate (12:15).