Yahya related to me from Malik that he had heard that Umar ibnal-Khattab had heard in a letter from Iraq that a man said to hiswife, "Your rein is on your withers (i.e. you have free rein)." Umaribn al-Khattab wrote to his governor to order the man to come to himat Makka at the time of hajj. While Umar was doing tawaf around theHouse, a man met him and greeted him. Umar asked him who he was, andhe replied that he was the man that he had ordered to be brought tohim. Umar said to him, "I ask you by the Lord of this building, whatdid you mean by your statement, 'Your rein is on your withers.'?" Theman replied, "Had you made me swear by other than this place, I wouldnot have told you the truth. I intended separation by that." Umar ibnal- Khattab said, "It is what you intended."
USC-MSA web (English) reference: Book 29, Hadith 5
Arabic reference: Book 29, Hadith 1157