Sa’d bin Ubaidah (may Allah have mercy on him) says that I was sitting in a gathering with Sayyiduna Ibn Umar (may Allah be pleased with them both). Sayyiduna Ibn Umar (may Allah be pleased with them both) heard a man in another gathering swear by «لا وابي» , so he threw pebbles at him and said: Sayyiduna Umar (may Allah be pleased with him) used to swear like this, but the Prophet (peace and blessings be upon him) forbade him from this, saying that it is shirk (associating partners with Allah).