The book was Evangelism and the Sovereignty of God by J.I. Packer. Which, as a side note, I think that if I ever become an author I am going to use my initials as well. There is something quite awesome about the initials (for example, C.S. Lewis, J.R.R. Tolkien, C.H. Spurgeon, and the like). Anyway, this book was a challenging book for me. Not in the respect of the words used, but rather in the content. The premise of this book is since God is sovereign over all things, including salvation, what role does the Christian play in evangelism. And the answer is, a huge role.
As Christians, our lives should be devoted to the vocation of sharing with others the gospel of Jesus Christ. We need to be people who share the death of Jesus Christ for the forgiveness of all sins, the burial, and the resurrection. However, many times, I fail to do so. Not because of the intense persecution that I face, but rather just that fear of not knowing every question that comes my way, the fear of man, the doubt of the power behind the gospel, and just the sheer discouragement of feeling ineffective in my sharing. And that is where God's sovereignty is so sweet. The Apostle Paul states that it was he who planted, Apollos who watered, and God who grew the people who heard the gospel. In the same way, when we plant the seed, God is the one who does the growing. It is nothing that we can do, but it is all on God, and HE ALWAYS COMES THROUGH.
Therefore, be encouraged that when you evangelize, it is never done in vain. Even when you feel discouraged or frustrated, God is always there and His word doesn't return void. I definitely recommend this book to anyone! God Bless!