The purpose of training is to tighten up the slack, toughen the body, and polish the spirit.
— Morihei Ueshiba

In marriage, a man becomes slack and selfish, and undergoes a fatty degeneration of his moral being.
Robert Louis Stevenson slack quote

He also who is slack in his work is brother to him who destroys. Proverbs 18:9
— Bible

Everybody favours free speech in the slack moments when no axes are being ground.
— Heywood Broun

The secret of popular writing is never to put more on a given page than the common reader can lap off it with no strain whatsoever on his habitually slack attention.
— Ezra Pound