Matthew Poole and continuators on 1 John 5:16

16 If any man see his brother sin a sin which is not unto death , he shall ask, and he shall give him life, for them that sin not unto death : there is a sin unto death, I do not say he shall pray for it.

Viz. That appears not obstinate and incurable; he shall ask, i. e. with confidence, as v. 14. But there is a Sin unto death, i. e. which doth not barely deserve Death, as all Sin doth, nor which argues a Person to be probably in a present State of Death of Unregeneracy, which the sinful ways may do of many that never made Profession; but of such as have apostatized from a former specious Profession into Heresy and Debauchery, and continue obstinate therein, against all Methods of Recovery; that are, as Iude 12. even twice dead, &c.

i. e. I do not give that encouragement to pray for such, with that hope and expectation of Success as for others; tho he doth not simply [illegible: 1 letter]orbid praying for them neither.

Marginal references: Jam. 5.14, 15.; Mat. 12.31, 32. Mark 3.29. Heb. 6.4. & 10.26.