Qais was the son of Sad Ibn Ubadah, the chief of the tribe of Khazraj and one of the companions of the Noble Prophet (s.a.w). He never reneged his pledge of allegiance to the Commander of the Faithfuls(a.s) and supported him through thick and thin – transferring his loyalties to Imam Hasan (a.s) after the martyrdom of the Commander of the Faithfuls(a.s).
Qais, his father Sad and his grandfather Ubadah had possessed a public rest-house. In one of the battles during the time of the Noble Prophet (s.a.w), he was part of the army in which Abu Bakr and Umar were also present. Sad would borrow money from his friends and spend it over his fellow-companions. Abu Bakr and Umar discussed amongst themselves: “If we allow him act in this fashion he shall soon squander away his father’s property”, and so they announced in public: “No one should lend money to Qais.”
When his father came to know of this he, after having recited the congregational prayers behind the Noble Prophet (s.a.w), stood up and said: “I complain before the Noble Prophet (s.a.w) and the people that Abu Bakr and Umar shall turn my son into a miser!”
In one of the battles he was appointed commander of the army. In that expedition which lasted for a few days he sacrificed nine camels for his fellow-companions, who were very few in number. When the Noble Prophet (s.a.w) was informed of this, he said: “Generosity is the conduct of this family!” When he fell ill very few people came to visit him. This surprised him and he sought to know the reason for this, whereupon he was informed: “The reason for this is that a lot of your wealth lies with the people. Being indebted to you, they are ashamed to present themselves before you!”
Hearing this Qais said: “May destruction strike the wealth that brings about separation amongst the brethren-in-faith!” Then, upon his instructions, it was announced in Madinah: “Whoever possesses any money belonging to Qais is henceforth the owner of that money for Qais has gifted the money to him.”
After this announcement the crowd that had flocked to his house was so great that the stairs leading up to Qais” room broke down and collapsed( Paighambar Wa Yaran, vol. 5, pg. 165; Qamus al-Rijal, vol. 7, pg. 399 )