It is narrated from Sa'd bin Ubaidah, he says: I was in a gathering with Sayyiduna Abdullah bin Umar (may Allah be pleased with them), when he heard a man sitting in another gathering say: "No, by my father's oath," so he threw a pebble at him and said: Sayyiduna Umar (may Allah be pleased with him) used to swear in the same way, but the Noble Prophet (peace and blessings be upon him) said: This is shirk (associating partners with Allah).