Thomas Manton (1620–1677) on Moral and Natural Ability

(3.) Impotency and weakness, which lieth in the wilfulness and hardness of their hearts. Our non posse is non velle. Our inability lies in our unwillingness: Ps. Iviii. 4, 5, 'They are like to the deaf adder, that stoppeth her ear, which will not hearken to the charmer, charming never so wisely;' Mat. xxiii. 37, 'How often would I have gathered thy children together as a hen gathereth her chickens under her wings, and ye would not?' Luke xix. 14, 'His citizens hated him, and sent a message after him, saying, We will not have this man to reign over us.' Now what more proper cure for all these evils than the word of God? Teaching is the proper means to cure ignorance, for men have a natural understanding. Warning of danger and mindfulness of duty is the proper means to cure slightness. And to remove their impotency (which lieth in their obstinacy and wilfulness), there is no such means as to beseech them with constant persuasions. The impotence is rather moral than natural. We do not use to reason men out of bare natural impotency, to bid a lame man walk, or a blind man see, or bid a dead man live; but to make men willing of the good which they rejected or neglected; in short, to inform the judgment, awaken the conscience, persuade the will: yet it is true the bare means will not do it without God's concurrence, the evidence and demonstration of the Spirit; but it is an encouragement to use these means, because they are fitted to the end, and God would not appoint us means which should be altogether in vain.

Thomas Manton, The Complete Works of Thomas Manton (London: James Nisbet & Co., 1873), 21:332.