You do not need permission to quote under 250 words with proper attribution. You may not change the wording and you must cite the title and date of the original work. For example,
Quote: Tim Keller has said, "Marriage is not basically romance garnished with friendship. It is basically friendship garnished with romance." (1)
Footnote: Timothy Keller, “Marriage as Friendship,” sermon presented at Redeemer Presbyterian Church: http://www.gospelinlife.com/sermons, 1991.
For anything exceeding 250 words, please contact the publisher of the book you are interested in, such as: