Narrated 'Amra:Aisha said, "the Prophet used to practice Itikaf in the last ten days of Ramadan and I used to pitch a tent for him, and after offering the morning prayer, he used to enter the tent." Hafsa asked the permission of 'Aisha to pitch a tent for her and she allowed her and she pitched her tent. When Zainab bint Jahsh saw it, she pitched another tent. In the morning the Prophet noticed the tents. He said, 'What is this?" He was told of the whole situation. Then the Prophet said, "Do you think that they intended to do righteousness by doing this?" He therefore abandoned the Itikaf in that month and practiced Itikaf for ten days in the month of Shawwal." (Sahih Bukhari 3.249)
Narrated 'Aisha:The Prophet intended to practice Itikaf and when he reached the place where he intended to perform Itikaf, he saw some tents, the tents of 'Aisha, Hafsa and Zainab. So, he said, "Do you consider that they intended to do righteousness by doing this?" And then he went away and did not perform Itikaf (in Ramadan) but performed it in the month of Shawwal for ten days. (Sahih Bukhari 3.250)
Narrated 'Amra bint 'Abdur-Rahman from 'Aisha:Allah's Apostle used to practice Itikaf every year in the month of Ramadan. And after offering the morning prayer, he used to enter the place of his Itikaf. 'Aisha asked his permission to let her practice Itikaf and he allowed her, and so she pitched a tent in the mosque. When Hafsa heard of that, she also pitched a tent (for herself), and when Zainab heard of that, she too pitched another tent. When, in the morning, Allah's Apostle had finished the morning prayer, he saw four tents and asked, "What is this?" He was informed about it. He then said, "What made them do this? Is it righteousness? Remove the tents, for I do not want to see them." So, the tents were removed. The Prophet did not perform Itikaf that year in the month of Ramadan, but did it in the last ten days of Shawwal. (Sahih Bukhari 3.257)