Musannaf Ibn Abi Shaybah 37308 — The words of Abu al-Darda

Salim bin Abi al-Ja'd narrates from Sayyidah Umm al-Darda (may Allah be pleased with her) that she (Sayyidah Umm al-Darda, may Allah be pleased with her) was asked: "What was the best deed of Sayyiduna Abu al-Darda (may Allah be pleased with him)?" She said: "Reflection."