(20) Chapter. Whoever took an oath that he would not enter upon his wife for one month and that month was of twenty-nine days.

Narrated Anas: Allah's Apostle took an oath for abstention from h is wives (for one month), and during those days he had a sprain in his foot. He stayed in a Mashrubah (an upper room) for twenty-nine nights and then came down. Then the people said, "O Allah's Apostle! You took an oath for abstention (from your wives) for one month." On that he said, "A month can be of twenty-nine days."