What do you know about the venerable Companion Thawban?

Thawban is one of the Prophet's household. Ibn al-Sakan narrated that the Prophet supplicated for his household. When Thawban asked if he was one of them, the Prophet replied to him on the third inquiry, "Yes, as long as you do not stand at the door of a fortress (suddah) or approach a ruler to ask him for something." "Suddah" here means the door of a sultan. Abu Dawud also narrated that the Prophet said, "Who will guarantee me that he will not ask [anyone for anything], and I will guarantee him Paradise?" Thawban said, "I will." And so, he never asked anyone for anything.