Ibrahim al-Nakha'i reports that Sayyiduna Hudhayfah (may Allah be pleased with him) said to Sayyiduna Ibn Mas'ud (may Allah be pleased with him): Are you not amazed at people who are (sitting) between your house and the house of Abu Musa, claiming that they are in i'tikaf (seclusion)? Sayyiduna Ibn Mas'ud (may Allah be pleased with him) said: "Perhaps they are right and you are mistaken."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9475