The Muslims were suffering many hardships in Makkah at the hands of the unbelievers. They were tortured and forced to leave Makkah and migrate to Madina.
When they arrived in Madina, they were welcomed by the Muslims of Madina. They were delighted to have their beloved Prophet (pbuh) and their brothers from Makkah living with them.
The Muslims had left everything behind and were very poor. The Prophet (pbuh) decided to form a brotherhood between the Makkan Muslims (Muhajiroon) and the Muslims of Madina (Ansars). Amongst them was Salmaan who was paired with Abu Darda.
One day Salmaan visited Abu Darda and found that Abu Darda's wife was dressed in shabby clothing. He asked her about her clothes and she replied that Abu Darda had no love for the luxuries of this life.
When Abu Darda came, Salmaan asked him to eat with him. Abu Darda replied that he was fasting but Salmaan still insisted, saying that I will not eat until you have eaten. They both ate food together.
At the early part of the night, Abu Darda got up to pray but Salmaan forced him to sleep. In the late part of the night, both brothers got up and prayed Tahajjud salah together.
Salmaan later explained to him that your Lord has a right over you, your body has a right over you and your family have a right over you. You need to give each its right (you need to have a balanced life without too much of one thing).