I heard the Messenger of Allah ﷺ say, "Stand, Bilal, and give us comfort with the prayer."
سمعت رسول الله ﷺ يقول: قم يا بلال، فأرحنا الصلاة.
Abu Dawud (4986) and Ahmad (23154) both narrated it from the hadith of Israil, who said, our teacher Uthman bin Mughira narrated to us, from Salim bin Abu Jaad, from Abdullah bin Muhammad Ibn Hanafiya, who said, "My father and I set out to visit a relative by marriage of ours from the Ansar who was ill. The time for prayer came, so he said to one of his household, 'Girl, bring me water for wudu so that I may pray and find rest.'" He said, "We found this strange from him, so he said, 'I heard the Messenger of Allah ﷺ say,'" then he related the hadith. Its chain of transmission is sahih.Abu Dawud (4985) and Ahmad (23088) both narrated it through another route, from Misar bin Kidam, from Amr bin Mura, from Salim bin Abu Jaad, from a man of Aslam, as it appears in Ahmad, while in Abu Dawud it is a man of Khuza, that the Prophet ﷺ said, "O Bilal, call the adhan for prayer, and let us find rest through it."If this route is sound, it serves as corroboration for the first route. It has also been narrated as a mursal report from Muhammad bin Hanafiya, and the ruling belongs to whichever version has a connected chain.As for his saying, "Let us find rest through prayer," it means that we become free through prayer, since the heart is preoccupied with it. It has also been said that its meaning is that his preoccupation with prayer was itself a source of rest for him, but this meaning does not fit well in this context.