Ping to a thought provoking subject.
"Who shall separate us from the love of Christ? Shall tribulation, or distress, or persecution, or famine, or nakedness or peril, or sword? As it is written, For thy sake we are killed all the day long; we are accounted as sheep for the slaughter. Nay, in all these things we are more than conquerors through Him that loved us. For I am persuaded, that neither DEATH, nor LIFE, nor angels, nor principalities, nor powers, nor things present, nor things to come, nor height, nor depth, nor any other creature shall be able to separate us from the love of God, which is in Christ Jesus our Lord." (Rom. 8:35-39).
Our life cannot separate us. Our death cannot separate us, if we are in Christ. And we are in Christ if we are saved.
So, what is it that a Christian loses if he takes his life? And what is it that Satan gains?
"Now then we are ambassadors for Christ, as though God did beseech you by us; we pray you in Christ's stead, be ye reconciled to God. For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him."2 Cor. 5:14-21.
Satan has two goals. To keep unbelievers from the Cross and the gospel of their salvation. And to keep believers from preaching the cross and the gospel of their salvation to unbelievers.
When a believer commits suicide, he has given up his God given commission to preach the finished work of Christ to unbelievers. And has effectually given Satan another chance to deceive unbelievers. Someone who may have been reached by the gospel of God's grace by that person who decided to end his life. That is why suicide is so bad. It cuts off another chance to hear/preach the gospel of the grace of God. That believer was and will always be in Christ. That is God's promise to us. But his work in Christ's stead, preaching the reconciliation of God and man has forever been cut off.