We bear in our own bosom a nest of turbulent thoughts, which, like busy gnats, will be buzzing about us while we are in our most inward and spiritual converses. Many wild beasts lurk in a man’s heart, as in a close and covert wood, and scarce discover themselves but at our solemn worship.

No duty so holy, no worship so spiritual, that can wholly privilege us from them. They will jog us in our most weighty employments, that, as God said to Cain, sin lies at the door, and enters in, and makes a riot in our souls. As it is said of wicked men, they cannot sleep for multitude of thoughts (Eccles 5:12), so it may be of many a good man, he cannot worship for multitude of thoughts.

—Stephen Charnock
The Complete Works of Stephen Charnock, 1:327–328.