Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says: On the evening of the day of Badr, when the captives were being bound in fetters, the Messenger of Allah (peace and blessings be upon him) spent the first part of the night awake. His (peace and blessings be upon him) Companions said: O Messenger of Allah! Why are you not sleeping? (Al-Abbas had been taken captive by a man of the Ansar.) The Messenger of Allah (peace and blessings be upon him) said: "I have heard the sound of my uncle al-Abbas crying." So they untied him. He fell silent, and the Messenger of Allah (peace and blessings be upon him) went to sleep.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18145