9 The heart is deceitful above all things, and desperately wicked: who can know it? 10 I the LORD search the heart, I try the reins, even to give every man according to his ways, and according to the fruit of his doings.

The heart of man, in his corrupt and fallen state, is false and deceitful above all things; deceitful in its apprehensions of things, calling evil good and good evil, putting false colours upon things, crying peace to those to whom peace does not belong, and cheating men to their own ruin; deceitful in the hopes and promises which it excites and nourishes, and in the assurances which it gives.