I like reading your posts and your threads because they raise interesting, relevant points with a bit of humility and insight.
Here is my take on 1 John 5:13-16.
13 These things I have written to you who believe in the name of the Son of God, so that you may know that you have eternal life.
John is addressing a pressing question, common among Christians. According to the Gospel, Jesus saves. We get that. What we really want to know is, "will Jesus save ME in particular." And it isn't a simple matter of giving mental ascent to the doctrine. So, John says, "I'm writing this to you who believe so that YOU may know that YOU, in particular, have eternal life. John is speaking to those who lack confidence in their eternal status.
14 This is the confidence which we have before Him, that, if we ask anything according to His will, He hears us. 15 And if we know that He hears us in whatever we ask, we know that we have the requests which we have asked from Him.
This is John's confidence building answer. God has promised to grant eternal life to all sinners who repent with contrition and honesty, and become disciples of Jesus Christ, walking in the way he taught us. Asking for forgiveness, and pardon, and restoration, and eternal life are all according to God's will. And if we ask God for these things, under those conditions, then we can be sure we have them.
16 If anyone sees his brother committing a sin not leading to death, he shall ask and God will for him give life to those who commit sin not leading to death.
Here John helps those who can't bring themselves to ask God for forgiveness on their own. In rare cases, someone might say, "I don't deserve his love or forgiveness. Will you pray with me? or, "will you pray for me?" John gives us permission to pray for them, giving us assurance that God will respond to such a prayer. Some people are so filled with self-loathing that they just can't take the first step without help.
There is a sin leading to death; I do not say that he should make request for this.
Here John is speaking to the case whereby a person has decided to reject the whole idea of God, religion, and everything. Jesus refereed to this attitude as the unforgivable sin. Blaspheme of the Holy Spirit isn't merely calling the Holy Spirit a liar. It is that; but the sin leading to death, is any act of rebellion that signals an irreconcilable hostility against God, a willful antipathy to God, or even a complete lack of interest.
John makes no promises with regard to these people. We can pray for them out of love and concern, but we can't have the same confidence with these prayers that we have for our other prayers.
Thanks again for your posts. I enjoy reading them.