Back to the book I found, The Art of Divine Contentment by Thomas Watson, c.1620-1686
It is a small hardcover book with only 133 pages. The chapters are only 2-3 pages and could be used as a devotional. I'm on chapter 8 and found early in the book this quote. This is a great little book.
"The Word must not only fall as dew that wets the leaf, but as rain which soaks to the root of the tree and makes it fruitful."