I have not had a close friend commit suicide, so I can’t speak to you from personal experience. My wife and I lost our first child when he was 3 ½ months old, and I do know what that was like. God gave us great peace in the midst of our pain.
The first think that we must always say is that suicide is sin. God forbids us to murder (beginning at Genesis 9:6), and thus taking our own life is wrong as well. To put it plainly, suicide is sin. It is a sin that is especially tempting to two kinds of folks: (1) those who believe there is nothing after death; and, (2) those who are assured that heaven awaits them after death (Christians). I do not believe that suicide is an unpardonable sin for a Christian, for Christ died to save us from all our sins. We don’t go to heaven because we stop sinning altogether as Christians, but because Christ died for our sins. Death (even death by one’s own hand) keeps no Christian from heaven, though we will have a lot of explaining to do when we get there. Death by one’s own hand deprives us of seeing how God would have faithfully provided for our needs if we had remained behind and waited for Him to turn our suffering into something good (Romans 8:28). Death for the one who does not trust in Christ is much more terrifying, because it takes us to judgment without any further opportunity to repent (Hebrews 9:27).
What you are telling me is a very normal response to the loss of a close friend by suicide. Those left behind by suicide may very well be a sense of guilt. You may be asking yourself, “Should I have seen this coming? Could I have prevented it? Was there something I should have said or done that I did not do or say?” You will be tempted to repeatedly go back through your last days and months with your friend, wondering if he gave you any hints of what he was planning to do. These are the times when we must remember that all of our days are numbered by God and that no one dies before it is God’s time (Psalm 139:16).
You will find that even some of the saints of old wished to die, including Job in the midst of his suffering (Job 3:10-11), Elijah (1 Kings 17), and Jonah (Jonah 4:3). In each of these cases, the thinking of the one who wished to die was wrong. They were suffering and they wanted the pain to end. I would encourage you to read Psalm 73, to see how Asaph came to see his suffering as a blessing, and not as a curse. He saw that suffering drew him nearer to God. Pain is a normal part of our experience as those who live in a fallen, sinful world (Romans 8:18ff.). It makes us hope for heaven, trusting our lives to God while we continue to live in this world.
I hear you talking much about pain, and I know that your pain is very real. Pain is a part of the consequence of living in a fallen world, because God promised Adam and Eve and their descendants pain, due to their sin (Genesis 3:16-19). This pain should make you look forward to heaven, but it should also turn you to God to enable you to endure it to God’s glory (see 2 Corinthians 1:3-11; 4:16—5:10; James 1:2-8).
I pray that God will give you a great sense of hope in the midst of your pain, and that your friend’s death will be used of God for good, in your life and the lives of others. You may wish to look at the lesson I once did on Psalm 73.
My prayers are with you.