There are two causes which require such things to be preached. The first is, the humbling of our pride, and the knowledge of the grace of God. the second is, Christian faith itself.
First, God has promised certainly His grace to the humbled: that is, to the self-deploring and despairing. But a man cannot be thoroughly humbled, until he comes to know that his salvation is utterly beyond his own powers, counsel, endeavours, will, and works, and absolutely depending on the will, counsel, pleasure, and work of another, that is, of God only.