There are two outstanding classics on the subject of conversion: A Call to the Unconverted, Richard Baxter; and, An Alarm to the Unconverted, Joseph Alleine.
Richard Baxter was a bright and shining light in the golden age of theology, the seventeenth century. Not only was he the most voluminous author of his day (72 volumes), but also his shepherding of his flock at Kidderminster was so phenomenal that it stands as a marker for all other pastors and evangelists. He practiced what he teaches in this book. The host of conversions under his preaching testifies to the power of the message in A Call.
Baxter was always plain spoken to sinners: "Whoever loves earth above Heaven, and fleshly prosperity more than God, is a wicked, unconverted man "
"We are commanded to beseech and entreat you to accept the offer and turn; to tell you what preparation is made by Christ; what mercy stays for you; what patience waits on you . . .how certainly and unspeakable happy you may be if you will. We have indeed a message of wrath and death; yea, of a twofold wrath and death; but neither of them is our principal message. We must tell you of the wrath that is on you already, and the death that you are born under for the breach of the law of works. But this is only to show you the need of mercy, and to provoke you to esteem the grace of the Redeemer. . . . Our telling you of your misery is not to make you miserable, but to drive you out to seek for mercy. It is you who have brought this death on yourselves. We tell you also of another death, one even remediless, and much greater torment that will fall on those who will not be converted. . . This is the last and saddest part of our message. Wearefirst to offer you mercy, if you will turn." (Pp. 21, 22).