Last night signalled the start of the last 10 days and nights of Ramadan (which could be nine days and nights by the way). It is the hastening to the end of the blessed month, when the Rasool saws woke his spouses during the nights to pray, when Aishah r.a. reports that the Prophet saws would tighten his waist belt, pray all night, and keep his family awake during the night. The increase in acts of ibaadah is not to be confused with itikaaf – that time of seclusion which the Prophet saws, as he did with the taraweeh, took particular care to ensure was not considered a fard (compulsory) act. Please note that this is only my interpretation – others have interpreted it to mean only that one can leave itikaaf even though one has made the intention to spend the time in itikaf.
“When I saw that, I ordered my tent to be set up, and some of the Prophet’s wives followed suit. When he [the Prophet] prayed the morning prayer, he saw all of the tents, and said: “What is this?” They said: “We are seeking obedience (to Allah and His Messenger).” Then he ordered his tent and those of his wives to be taken down, and he delayed his i`tikaf to the first ten days (of Shawwal).”[