The principal matter of our prayers concerneth faith and unbelief. So the apostles prayed in a particular manner, -Lord, increase our faith-- and so the poor man prayed in his distress, -Lord, help thou mine unbelief.- I cannot think that they ever pray aright who never pray for the pardon of unbelief, for the removal of it, and for the increase of faith. If unbelief be the greatest of sins, and if faith be the greatest of the gifts of God, we are not Christians if these things.