Ubu Juhaifah narrated from his father who said:
The Messenger of Allah (s.a.w) made a bond of brotherhood between Salman and Abu Ad-Darda. Salman went to visit Abu Ad-Darda, and saw Umm Ad-Darda wearing shabby clothes, So he said: 'Why are you wearing such shabby clothes?' She said: 'Your brother Abu Ad-Darda has no interest in the world.' So when Abu Ad-Darda arrived, he prepared some food for him (Salman) and said: 'Eat, for I am fasting.' He said: 'I shall not eat until you eat.' He said: So he ate. When night came Abu Ad-Darda started to leave and stand (in prayer), but Salman said to him: 'Sleep.' So he slept. Then he went to stand (in prayer) but he said to him: 'Sleep'. So he slept. When the morning (Fajr) came,Salman said: 'Get up now.'So he got up to perform Salat. Then he (Salman) said: 'Indeed your self has a right upon you, your Lord has a right upon you, your guest has a right upon you, and your family has a right upon you. So give each the right they are due. The Prophet (s.a.w), and that was mentioned to him, so he said: 'Salman has told the truth.'