Philip Graham Ryken on praying and Calvinistic evangelism:
One way to test the claim that every Christian is a Calvinist at prayer is to consider how believers pray for the unconverted. Imagine for a moment that God is not sovereign in grace, but that salvation ultimately depends on the sinner’s own choice. How then should we pray? Do we say: “Dear Lord, I realize that there may not be much that you can do about this, but if there is, please help my friend somehow to become a Christian”? Of course no one actually prays this way; the very idea is absurd. But what makes it so absurd is that, deep down, every Christian believes in the sovereignty of God’s grace. When we pray for sinners to be converted, therefore, we ask God to do something for them that we know they are utterly incapable of doing for themselves. We ask God to invade their minds, change their hearts, and bend their wills so that they will come to him in faith and repentance. In short, in our intercession we depend on God to save them. This attitude of dependence ought to characterize the Christian’s entire approach to evangelism. True evangelism is entirely dependent on God for its success: the regeneration of the sinner’s mind and heart is the work of God’s Spirit. It does not depend on the Christian’s saying the right words or using the most effective technique. The true Calvinist surrenders to God’s will in sharing the gospel because God’s sovereignty in grace gives the only hope of success [What is a True Calvinist? (Phillipsburg: P&R Publishing, 2003), 20].