Is it suicide a sin? My father did so. and since he was not a christian I wonder where did he go after he died.
Something tells me that you know the answer to your own question. Of course it is a sin to take one’s life. I cannot give you a passage which teaches specifically that suicide is a sin, but based on a number of important biblical principles, I have to conclude that God is not glorified when a human being takes their own life. Let me list a few principles on which I have to conclude it is not a righteous act to take our own life.
1. Suicide is murder. Not that we need this passage to know that murder is sin, I will nevertheless mention Revelation 21:8. It is no more pleasing to God to take the life of another person than to take one’s own.
2. To take one’s life is, in most cases (I want to be careful not to judge here) is the ultimate act of lack of faith. Hebrews11:6 "And without faith it is impossible to please God, because anyone who comes to him must believe that he exists and that he rewards those who earnestly seek him. It is not sinful to have feelings of discouragement and depression, but to act on that depression and decide not to trust God’s way out is to sin.
3. To take one’s life, in most cases, is an extreme act of selfishness. If you have been around suicide, you know that those left behind are left confused, angry, hurt, feeling guilty. The loved ones of those who commit suicide are hurt on the deepest possible level by suicide in most cases. I believe that for a person in excruciating pain who is near death to take his or her life may have somewhat different emotional effect, but even in this case, I believe it is an act of selfishness.
So, yes, suicide is an sinful act.
I have a feeling that this is not really the reason you asked me the question. You already knew that suicide was a sin. The problem most of us have with suicide is that we have the impression it is a sin which will keep people out of heaven. There are two reasons we have this idea. One is that the Catholic Church has taught for hundreds of years that suicide is a "mortal" sin. In other words the Roman Catholic teaching has been that anyone who commits suicide automatically goes to hell. The problem with this teaching is that it is not biblical. The other reason this idea that suicide is somehow a "worse" sin than others is that clearly suicide is the last act of one’s life. Somehow, human logic tells us that suicide as a last act of our life is like spitting in the face of God–that it is an unforgiveable sin.
I do not agree with this conclusion. It is not biblical. Suicide is a sin, but it is not a "special" sin. The impact of suicide is extreme, no doubt, but biblically it will be hard to make the case that it is a sin which automatically will keep one out of heaven. Imagine this scenario. A faithful Christian is in a fatal car accident. Right before impact, he or she shouts out a profanity. The last act of their life is a sinful act. Does this somehow wipe out a life as a faithful disciple of Jesus? No!
It is not our place to judge. I believe that for a Christian to take their own life is not an act of faith. It is a sin, but this sin will not, in and of itself keep one from heaven. A friend of mine was a preacher and one of the most faithful Christians I have known. In his sixties he got cancer. He was suffering horrific pain. In addition, his brain and his thinking was altered by his cancer. Unfortunately, this brother in Christ made the decision to take his life. I believe that this was a sin. I know the terrible impact this act had on his family. However, I cannot judge this brother. In fact, I believe he will be in heaven. Until I am in this terrible situation myself, I do not want to judge someone who is.
Now, about your father, I am guessing that his suicide has had a devastating impact on your life. I do not believe your father will go to hell because he killed himself. However, if you are right that he was not a Christian when he died, then I am afraid that the Bible teaches that he was not saved and will not go to heaven. The Bible teaches that there is no way to be saved and to go to heaven without being forgiven of our sins through Jesus Christ. (John 12:47-50, John 14:6, Acts 4:12, Luke 13:1-5, Romans 3:9-26 and many more). No one will be saved unless they put their faith in Jesus Christ, repent of all their sins and are baptized into Christ. I know that this is very hard to accept, but as Jesus said, the gate is narrow and the way is difficult which leads to heaven (Matthew 7:13-14). You and I are not the Judge, but if your father was not a Christian, then if I understand the Bible, he was not saved and he will not go to heaven.
Now, please do not take the word of a person you never met for this. You should study out the scriptures for yourself. However, let me comfort you with these words. I believe that the Bible does NOT teach that anyone who commits suicide will go to hell. If your father was saved before he did this, then he will be in heaven. If he was not saved, then he will not be in heaven, biblically, but his taking of his life, by itself, will not change his status before God.
It is possible that this answer has comforted you. It is also possible that it has made you feel even worse than you did before. I pray that it is the former. In any case, please do not take my word on this, but consult the scriptures and seek comfort and advice from a mature Christian who can help you to deal with the emotional impact, both of what your father did and of the biblical teaching.
I hope this has helped.