As a Calvinist, one of the most common things I get accused of is not witnessing. “Where is the motivation to witness,” one might say, “If God has already decided who's going to heaven and hell?”
This book, Evangelism and the Sovereignty of God by J.I. Packer, addresses this question beautifully and concisely. Whether you believe in predestination or free-will (or if you're undecided!) I highly recommend this short book. The book makes no distinction between Calvinist or Armenian: “There is a long-standing controversy in the church as to whether God is really Lord in relation to human conduct and saving faith or not....the situation is not what it seems to be. For it is not true that some Christians believe in divine sovereignty while others hold an opposite view. What is true is that all Christians believe in divine sovereignty, but some are not aware that they do, and mistakenly imagine and insist that they reject it. What causes this odd state of affairs?” Well, you'll have read the book and find out!
In the book, Packer draws two main conclusions: “1. The sovereignty of God in grace does not affect anything that we have said about the nature and duty of evangelism.” but in fact, “2. The sovereignty of God in grace gives us our only hope of success in evangelism.” He also poses several thought-provoking questions:
In summary, this book is an excellent brief description of how the sovereignty of God pertains to evangelism. But it also gives some practical tips on witnessing. It's a must-read, no matter what you believe.
Packer, J. I. Evangelism and the Sovereignty of God. Leicester: Inter-Varsity, 1979. Print.