Evangelism and the Sovereignty of God

If God is in control of everything, can Christians sit back and not bother to evangelize?  Or does active evangelism imply that God is not really sovereign at all?  Through a careful review of the biblical material, J. I. Packer shows in this classic study how both of these attitudes are false.  "Far from inhibiting evangelism," Packer writes, "faith in the sovereignty of God's government and grace is the only thing that can sustain it, for it is the only thing that can give us the resilience that we need if we are to evangelize boldly and persistently."