Hazrat Rasulullah (sallallahu ‘alaihi wasallam) and the Sahaabah (radhiyallahu ‘anhum) had sat in I’tikaaf during the last ten days of Ramadhaan. There are great virtues mentioned in the Mubaarak Ahaadith for those who sit in I’tikaaf during the last ten days of Ramadhaan. Hence, if one is able to sit in I’tikaaf and fulfil this sunnah then one should do so.
Regarding the one sitting in I’tikaaf, Hazrat Rasulullah (sallallahu ‘alaihi wasallam) said, “The mu’takif (the one sitting for I’tikaaf in the musjid) stays away from committing sins, and at every moment (while he is in I’tikaaf), he receives the reward for carrying out the various forms of ibaadah that he used to carry out when he was not in the state of I’tikaaf.” (Sunan Ibnu Maajah #1781)
In another Hadith, Hazrat Rasulullah (sallallahu ‘alaihi wasallam) said, “Whoever sits in I’tikaaf for a day, seeking the pleasure of Allah Ta‘ala, Allah Ta‘ala will place between him and the fire of Jahannum three trenches, and each trench is as vast as the distance between the east and the west.” (Shu’abul Imaan #3679 & Majma’uz Zawaa’id #13716)