We cannot attain to the understanding of Scripture either by study or by the intellect. Your first duty is to begin by prayer. Entreat the Lord to grant you, of His great mercy, the true understanding of His Word. There is no other interpreter of the Word of God than the Author of this Word, as He Himself has said, "They shall be all taught of God" (John 6:45). Hope for nothing from your own labors, from your own understanding: trust solely in God, and in the influence of His Spirit. Believe this on the word of a man who has experience.
Christ is the Master; the Scriptures are only the servant. The true way to test all the Books is to see whether they work the will of Christ or not. No Book which does not preach Christ can be apostolic, though Peter or Paul were its author. And no Book which does preach Christ can fail to be apostolic, although Judas, Ananias, Pilate, or Herod were its author.