The book is A Gospel Primer for Christians: Learning to See the Glories of God's Love and in my opinion it is a must-read for every growing Christian.
The premise is that we need to rehearse the Gospel to ourselves daily, moment-by-moment in order to live it. Our natural tendencies take us in the opposite direction, and only the Gospel can change our minds and hearts.
In the book, Vincent gives 31 reasons why we should rehearse the Gospel, the Gospel in simple prose form, the Gospel in poetic form and a short chapter on what led him to write this book. The whole book could be read in one sitting, but it is worth reading very slowly. I'm reading two or three of the 31 reasons each morning with my quiet time, but I know I'm going to want to go back and read them over and over again.
Just to whet your appetite...
Reason #17: The Gospel Gives Liberation from Self-Love
...His astonishing love for me renders self-absorption moot and frees me up to move on to causes and interests far greater than myself...the gospel reveals to me the breathtaking glory and loveliness of God, and in so doing, it lures my heart away from love of self and leaves me enthralled by Him instead. The more I behold God's glory in the gospel, the more lovely He appears to me. And the more lovely He appears, the more self fades into the background like a former love interest who can on longer compete for my affections.
Preaching the gospel to myself every day reminds me of God's astounding love for me and also of His infinite worthiness to be loved by me above all else. These reminders deliver a one-two punch to my innate self-absorption and leave me increasingly absorbed with Christ and with God's ultimate plan to gather together all heavenly and earthly things to Him. (see 2 Cor. 4:4, Phil. 3:7-8, Eph. 1:9-10, 1 Cor. 15:28)