Moody Bible Institute's Today in the Word, September, 1991, p. 30
Speaking to a large audience, D.L. Moody held up a glass and asked, "How can I get the air out of this glass?"
One man shouted, "Suck it out with a pump!"
Moody replied, "That would create a vacuum and shatter the glass."
After numerous other suggestions Moody smiled, picked up a pitcher of water, and filled the glass. "There," he said, "all the air is now removed." He then went on to explain that victory in the Christian life is not accomplished by "sucking out a sin here and there," but by being filled with the Holy Spirit.