1 John 5:16
If anyone [of you] observes his brother [or sister] sinning [in a way that would not lead] to [spiritual] death, he should ask [God, in prayer, to help that person], and God will give him [spiritual] life, [that is], to such ones, provided their sin is not leading to [spiritual] death. There is such a sin that leads to [spiritual] death. [See Heb. 6:4-6; I Tim. 5:6; Heb. 10:26-27; II Pet. 2:20-22]. I am not suggesting that you should ask [God, in prayer] about such a situation.
Hebrews 6:4-6
[These are people] who were once enlightened [by the Gospel message], who had experienced the gift from heaven [i.e., forgiveness, never ending life, etc. See Rom. 6:23], who had partaken of the Holy Spirit [See Acts 2:38],
Matthew 12:31-32
Therefore I tell you, people will be forgiven of every sin and abusive word spoken [against God]. But abusive words spoken against the Holy Spirit will not be forgiven.
Luke 12:10
And every person who speaks an [abusive] word against the Son of man will be forgiven of it, but the person who speaks abusive words against the Holy Spirit will not be forgiven of it.
Mark 3:28-30
Truly I tell you, all of mankind's sins and the abusive language that they use in speaking against God [and men] can be forgiven.
John 17:9
I am praying for them [i.e., the apostles]; I am not praying for the world, but for those whom you gave me, who belong to you.
2 Timothy 4:14
Alexander the metal worker did me much harm; the Lord will repay him for what he did.
Hebrews 10:26-31
For if we go on sinning intentionally, after we have received the full knowledge of the truth, there is no longer any sacrifice for [our] sins.
James 5:14-15
Is anyone among you sick? [Then] he should call for the elders of the church and they should pray for him, after pouring [olive] oil on him in the name [i.e., by the authority] of the Lord.
2 Peter 2:20-22
For if people who have escaped from the defiling practices of the world by coming to know our Lord and Savior Jesus Christ, become tangled up in them again, and are overcome by them, these people are worse off than before they were converted.