. . . the ‘sin unto death’, as is
today fairly generally agreed, refers to the sin of apostasy. The brotherly
duty of intercession is expressly suspended in this particular case; for the
apostate is no longer a brother, and the man who has abandoned the faith and
plunged back into the heathenism is truly lost. Hence it is here and here alone
that the promise that prayer will be heard (1 John. 5:16), which within
Christianity itself is valid without restriction of any kind, finds its limit.
Hebrews speaks explicitly of those who have tasted the heavenly gift, been made
partakers of the Holy Spirit, and then have nevertheless fallen away: it is
impossible to ‘renew’ such people again to repentance. This means what it says:
it is impossible to bring them back to repentance, not, it is impermissible, if
they should come to repentance, then to pronounce their forgiveness. The
meaning of ανακαινιζειν here is
attested specially in Hermas, Sim. IX, 14, 3. Hebrews too, therefore, considers
that there is no prospect of the conversion of those who have once apostasied. (Hans
Von Campenhausen, Ecclesiastical Authority and Spiritual Power in the Church
of the First Three Centuries [trans. J. A. Baker; London: Adam and Charles
Black, 1969], 223 n. 41; note that Von Campenhausen does not believe, as some Protestants do, that the "sin unto death" means a sin that leads to physical death; instead, it is one that results in a person forfeiting their salvation)