Verse 16; There is sin that brings death. Reformed Bible Study wrote, Some connect this sin with the unforgivable sin mentioned in Matt. 12:31, 32; Mark 3:28–30; Luke 12:8–10. More likely, John is referring to a stubborn refusal to accept the message of the gospel.
1 John 5:14-16; verse 14-15;1, When you’re seeking God will or according to His will meaning you’re interested in His will not your own will than God will hear your prayer than God will give confidence carry it out since acting on His will John Macarthur wrote ’” John already specified that answered prayer also depends on obedience to God’s commandments and avoidance of sin (3:21; Ps. 66:18; John 15:7; 1 Pet. 3:7). Since genuine believers know God’s Word (i.e., His will) and practice those things that are pleasing to Him, they never insist on their own will, but supremely seek God’s desires (Matt. 26:39–42).”
Verse 16-17 16 If anyone sees his brother committing a sin that does not bring death, he should ask, and God will give life to him—to those who commit sin that doesn’t bring death. There is sin that brings death. I am not saying he should pray about that. 17 All unrighteousness is sin, and there is sin that does not bring death. I’ll use the link you sent since I like Dr John Gil commentary which I enjoyed reading like Matthew Henry, Thomas Aquinas, and John Calvin where they wrote commentary on the Old & New Testament in which many Biblical scholars enjoy their works in the past, present and futures below are the link to all his commentaries
Verse 16; If anyone sees his brother committing a sin that does not bring death, Matthew 18; 15, states,” If your brother sins against you, go and rebuke him in private. If he listens to you, you have won your brother. Gils wrote following,” for fallen believers; for a “brother”; not in a natural or civil sense, but in a spiritual sense, one that is judged to be born again, and belongs to the family and household of God, and is a member of a Gospel church; and so is under the watch, inspection, and care of the saints; and is observed to sin, as the best of men are not without it, nor the commission of it, in thought, word, or deed: and this sin of his is a sin [which is not unto death
Resulting from Adam and Eve disobedience when they ate the forbidden fruit they died a spiritual death and eventually died physically death where Gil wrote, “every sin, even the least sin, is in its own nature mortal, or deserving of death; the proper wages of sin is death, yea, death eternal. However, those being chosen by God. Will fall asleep and their souls will wake up in heaven, 1 Corinthians 15; 5 Gil wrote, “yet none of the sins of God’s elect are unto death or issue in death; in fact; which is owing not to any different nature there is in their sins, or to their good works which counterbalance them; but to the grace of God, and to the blood and righteousness of Christ, by which they are pardoned and justified, and freed from obligation to punishment, or eternal death.”
However, their times when follow of Christ continue fall into sins even thou know it wrong they continue fall unto same sin again and again for example, the Apostle Paul in Romans 7; 15-18 For I do not understand what I am doing, because I do not practice what I want to do, but I do what I hate. 16 And if I do what I do not want to do, I agree with the law that it is good. 17 So now I am no longer the one doing it, but it is sin living in me. 18 For I know that nothing good lives in me that is, in my flesh. For the desire to do what is good is with me, but there is no ability to do it. Gil wrote,” that sin he sins is not a governing one in him; though he falls into it, he rises up out of it through divine grace and abides not in it; and he has a sense of it and is sorry for it, after a godly sort, loaths it, and himself for it; is ashamed of it, ingenuously confesses it, and mourns over it, and forsakes it. As scripture declares,’ or though the righteous fall seven times, they rise again. When sees a brother or sisters fall into sin they comfort them and pray for them and encourage them get up again. That is, God shall give the sinning brother life; by which may be meant comfort that which will revive his drooping spirits, and cause him to live cheerfully and comfortably, that so he may not be swallowed up with over much sorrow; or he shall grant a discovery of the pardon of his sin unto him, which will be as life from the dead, and will give him a comfortable hope of eternal life, of his right unto it, and meetness for it:
KJV Bible Study wrote,”may refer to blaspheming the Holy Spirit, rejecting Christ as Savior, rejecting the humanity or deity of Jesus, a specific sin such as murder (3:12, 15), or a life of habitual sin. Whatever it is, the sin seems to be a flagrant violation of the sanctity of the Christian community
Gils wrote,”here is a sin unto death;which is not only deserving of death, as every other sin is, but which certainly and inevitably issues in death in all that commit it, without exception; and that is the sin against the Holy Ghost, which is neither forgiven in this world nor in that to come, and therefore must be unto death; it is a sinning wilfully, not in a practical, but doctrinal way, after a man has received the knowledge of the truth; it is a wilful denial of the truth of the Gospel, particularly that peace, pardon, righteousness, eternal life, and salvation, are by Jesus Christ, contrary to the light of his mind, and this joined with malice and obstinacy; so that there is no more or other sacrifice for such a sin; there is nothing but a fearful looking for of wrath and fury to fall on such opposers of the way of life; and as the presumptuous sinners under Moses’s law died without mercy, so must these despiteful ones under the Gospel; see ( Matthew 12:31 Matthew 12:32 ) ( Hebrews 10:26-29 ) . Some think there is an allusion to one of the kinds of excommunication among the Jews, called “shammatha”, the etymology of which, according to some Jewish writers, is (htym Mv) , “there is death
To me one evident when you sin against the Holy Spirit you deny Jesus is Lord and his atoning on the cross. The Apostle Paul wrote,”Therefore I inform you that no one who is speaking by the Spirit of God says, “Jesus be cursed,” and no one can say, “Jesus is Lord,” except by the Holy Spirit.
However, someone commits a murder, and was found guilty, and was sentence to die and became a committed follower of Christ, and repented, confess and believe that Jesus took their sins. Than their sins will no longer remember in heaven. They eventually were executed due to the crime they committed before they accept the Lord the government was within right carryout this sentence As scripture declares,” Everyone must submit to the governing authorities, for there is no authority except from God, and those that exist are instituted by God.” Romans 13;1