There is quite a large number of Bible commentators and theologians that I consult when preparing a sermon or a Bible study, or just pursuing some question in my personal studies. However, the list is significantly shorter when it comes to people I always consult, whose commentaries I always purchase if they've written one on a book of the Bible I am studying, or if they've written a book on a particular topic that I am going to dig into. One of those people is Don Carson.
I have used his books in teaching through Philippians, in preaching through Matthew, and in studying various topics of theology and the Christian life. Several years ago I attended a pastor's conference where he was the key note speaker. Let me just say that God used him to encourage me in ministry for the next couple of years. The clip linked below will show you why - the man knows the gospel and lives in the Word.
Justin Taylor has posted a powerful illustration of the ground of the believer's assurance of salvation. This illustration came during one of Carson's talks at a recent Bethlehem College & Seminary Pastor's Conference. Take the time to watch it here. Regarding assurance of salvation, may this encourage you to look not to the amount of your faith but to the object of your faith - Jesus Christ crucified and risen.