The Messenger of Allah ﷺ said, "I have been harmed for the sake of Allah in ways no one else has been harmed, and I have been made to fear for the sake of Allah in ways no one else has been made to fear. Three days and nights once passed in which Bilal and I had no food fit for a living creature to eat, except for what Bilal could conceal under his armpit."
قال رسول الله ﷺ: لقد أوذيت في الله، وما يؤذى أحد، وأخفت في الله وما يخاف أحد، ولقد أتت على ثلاثة من بين يوم وليلة، ومالي وبلال طعام يأكله ذو كبد، إلا ما يواري إبط بلال.
Tirmidhi (2472), Ibn Majah (151), and Ahmad (12212) all narrated it, and Ibn Hibban (6560) graded it sahih, all of them through the hadith of Hammad bin Salama, from Thabit, from Anas, as mentioned, and its chain of transmission is sahih. Tirmidhi said, "Hasan sahih."As for his statement, "what would not cover the armpit of Bilal," it means it was such a small amount that it would fit under Bilal's armpit when he carried it.