"A young scholastic asked Alonso if it was necessary to sweep out his room three times each week, since Father Ignatius had prescribed that it should be done "at least every third day." The Society understood this to mean that twice each week was sufficient. But Alonso replied to the scholastic's question: 'My dear Brother, I sweep mine out four times each week, because the Rule orders it to be done at least three times. Now, that expression, 'at least' seems to me to require more, and so I sweep the room four times. That is safer.' "
From "The Wool Merchant of Segovia: The Life of St. Alphonsus Rodriguez" by Mabel Farnum c. 1945 p.107.