For personal reasons, I want to answer this question today. Here's how it was texted to us during church two weeks ago: Where does bible say suicide = going to hell?
NOWHERE does the Bible teach that committing suicide = going to hell. NOWHERE!
Suicide is a heinous, selfish sin. It is murder of self. And it devastates any family members or friends. This is one very intense reason why we must pay attention to any prolonged depression in our life, and out of love for God and others seek help and treatment with persistence, that we might stay short of the depth of despondency which could tempt us to steal ourselves from those who love us. I so admire people I know who tend toward deep depression, and continue to do the hard work of managing and healing that illness.
(Later addition: While taking one's own life volitionally is a 'sin' and not God's will for anyone, as in the preceding paragraph, I also need to point out and should have originally in this post: many if not most suicides involve some form of mental illness. It is not in my power nor my right to ever judge whether any specific suicide was an act of the person's clear volition, or if it was a final consuming act of their mental illness. This is not ours nor mine to judge. And is why I hope we can do more in and outside of the church to de-stigmatize mental illness, particularly clinical depression and bi-polar disorder, so that sufferers are less alone in society and in Christian community, with more people on their team, assisting them in their courageous battles to manage their condition and/or fight their battle. I have helped dear friends fight this battle for years. Their suffering breaks my heart, their persistent courage gives me strength. )
There are a couple of phrases in the New Testament that the Catholic church at some point attached to suicide, combined it with a theology of salvation by works (and the ability to lose salvation by 'bad works'). The connection between suicide and instant damnation was taught for a long time (I don't know when that teaching began or if it is current today, I doubt it and fervently hope not, yet it survives in cultural memory to the point that I have to address this directly at every funeral I preach when suicide is involved. I"m guessing this teaching started in the middle ages).
The biblical phrases are '...the unforgivable sin...' and '...sin against the Holy Spirit...' (you can search these passages at biblegateway.com). But NOTHING in those texts connects them to suicide. These verses refer to rejecting God completely, not some specific sin. The connection of suicide to hell is a human imposition onto the Scriptures of a hierarchy of sin relative to the grace of God.
Consider the following points: The Bible teaches salvation (reconciliation/compatibility of an unholy person to our holy God) by grace (God's part) through faith (our part) alone, NOT by works, that no one should boast (Ephesians 2:8). Let's take the case of two different professing Christians who took their own life, whose funerals I led. They put their faith in Jesus at some point in life, and God gave them grace (God exchanged the righteousness of Jesus for their sinfulness, through the power of the cross) - which means God forgave and cleansed them. Their sin no longer separated them from God at that point, they were given eternal life at that moment. Salvation by grace, through faith.
If suicide is some unique category of sin that sends them to hell, then salvation by grace is completely negated. That would mean their sin is stronger than the cleansing power of the blood of Jesus, that has been applied to their entire life through faith in Jesus. What a heresy!!!! Shut yo mouth!!!! Ridiculous!!! The atoning-for-sin sacrifice that God self-made through Jesus on the cross is the most powerful, redemptive, solid action in the universe. Any single sin of any single person is puny, infinitesimal, ephemeral in comparison.
But Mike (someone will say), they committed that sin and didn't live to confess it! Well, if I sin against my wife Angie and say something ugly to her this morning, hop in my car still smoldering with unjustified selfish anger, and get in a car wreck that kills me two minutes later - I will not have confessed that sin, yet that will not negate my salvation. When you put your faith in Christ, all sin is forgiven past, present and future. When a Christian sins after their conversion, it does not 'un-salvation' them - that would be returning to a false, unbiblical concept of salvation by being good enough for God, as well as maintaining my salvation by acting good enough for God; rather than allowing Jesus to be good enough on my behalf. No, when a Christian sins, it does not 'un-adopt' them from being a forgiven child of God, but what it DOES do is darken the relationship. Confession of that sin clears the air again.
By the way, those two funerals for friends of mine who took their own life? When I reach heaven, if the LORD allows such things, I intend to walk up to each of them and punch them in the mouth (sorry, that's what I want to do - perhaps I won't want to any longer in that moment). I am still angry about what they stole from their families and I hope I can tell them. (these are two specific friends with unique circumstances). But then I'll offer them a hand up, and embrace them tearfully, joyful to see them fully healed from their pain.
Ephesians 2:8,9 "For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God— not by works, so that no one can boast."