The whole Bible
"Once you are convinced that your people need — I say need — the whole Word of God, and you get over the shock to your indolent flesh that you are not in the ministry for an easy job, you simply roll up your sleeves, and having gathered, or being in process of gathering, the most helpful library of commentaries and reference books you can find, you get down to it: and book by book you give your people a balanced diet of the truth." (William Still, The Work of the Pastor