It is evil to justify killing (unborn babies) by the happy outcome of eternity for the one killed. This same justification could be used to justify killing one-year olds, or any heaven-bound believer for that matter. The Bible asks the question: "Shall we sin that grace may abound?" (Romans 6:1) And: "Shall we do evil that good may come?" (Romans 3:8). In both cases the answer is a resounding NO. It is presumption to step into God's place and try to make the assignments to heaven or to hell. Our duty is to obey God, not to play God.
John PiperHe shook my dozing soul and threw the cold water of reality in my face, so that life and God and heaven and hell broke into my world with glory and horror. (on CS Lewis)
John PiperWhen I pray for revival I pray first for the most radical thing: The utter devotion and allegiance of your hearts to Christ. That you would love Him so deeply and long for Him so passionately that His coming would be your great hope, and death would be gain, and life would be for Christ and His kingdom.
John PiperLife is not a straight line leading from one blessing to the next and then finally to heaven. Life is a winding and troubled road. Switchback after switchback. And the point of biblical stories like Joseph and Job and Esther and Ruth is to help us feel in our bones (not just know in our heads) that God is for us in all these strange turns. God is not just showing up after the trouble and cleaning it up. He is plotting the course and managing the troubles with far-reaching purposes for our good and for the glory of Jesus Christ.
John Piper