We proceed... to lay down and explain a principle, which is more or less distinctly recognized by writers on Christian experience; and which, by the common consent of those who have examined it, is very intimately connected with the progress and perfection of the interior Christian life. The principle is that of inward QUIETUDE OR STILLNESS, in other words, a true and practical ceasing from self.
This principle involves, in the first place, a cessation from all inordinate and selfish outward activity. It does not, it will be remembered, exclude an outward activity of the right kind. To entertain any idea of this kind, would be a great error. But it disapproves and condemns that spirit of worldly movement and progress, that calculating and self-interested activity, that running to and fro without seriously looking to God and without a quiet confidence in Him, which has been in all ages of the world the dishonor and the bane of true Christianity. How much of what may be called secular scheming and planning there is in the church at the present time! How much of action, prosecuted on principles, which certainly cannot be acceptable to a truly holy heart! While it exhibits much of true piety and much of the right kind of action, is it not evident, that the church exhibits a great deal also, both in its plans of personal and of public activity, of that restless, unsanctified, and grasping eagerness, which characterizes, and may be expected to characterize those who live and act, as if there were no God in the world! The principle of quietude or stillness decidedly condemns this injurious and evil course.
— edited from The Interior or Hidden Life (2nd edition, 1844) Part 3, Chapter 10 by Thomas Cogswell Upham. His blog is managed by Craig L Adams and can be found here: http://thomascupham.blogspot.com