Musnad Ahmad 3293

It was narrated from Ibn ‘Abbas (رضي الله عنه) that The Prophet (ﷺ) said: “The best days on which to be treated with cupping are the seventeenth, the nineteenth and the twenty-first." And he said: "I never passed by any group of angels on the night on which I was taken on the Night Journey but they said: You should adhere to treatment with cupping, O Muhammad.”