The Prophet (ﷺ) made a bond of brotherhood between Salman and Abu d-Darda'. Salman paid a visit to Abu d-Darda' and found Umm Darda' (his wife) dressed in shabby clothes and asked her why she was in that state. She replied: "Your brother Abu d-Darda' is not interested in (the luxuries of) this world. In the meantime Abu d-Darda' came in and prepared a meal for Salman. Salman requested Abu d-Darda' to eat (with him) but Abu d-Darda' said: "I am fasting." Salman said: "I am not going to eat unless you eat." So, Abu d-Darda' ate (with Salman). When it was night and (a part of the night passed), Abu d-Darda' got up (to offer the night prayer) but Salman asked him to sleep and Abu d-Darda' slept. After some time Abu d-Darda' again got up but Salman asked him to sleep. When it was the last hours of the night, Salman asked him to get up and both of them offered (Tahajjud) prayer. Then Salman told Abu d-Darda': "You owe a duty to your Rubb, you owe a duty to your body; you owe a duty to your family; so you should give to every one his due. Abu d-Darda' came to the Prophet (ﷺ) and reported the whole story. Prophet (ﷺ) said, "Salman is right".

[Al- Bukhari].