Musannaf Ibn Abi Shaybah 12886 — How they used to swear

Abd al-Rahman bin al-Aswad narrates from his father, who said: I was sitting with Sayyiduna Ibn Mas'ud (may Allah be pleased with him) on the roof of his house when the sun set. Sayyiduna Abdullah said: By the One besides whom there is no god, this is the time when the fasting person breaks his fast.