Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: The Prophet Muhammad (peace and blessings be upon him) saw Sayyiduna Umar bin Khattab (may Allah be pleased with him) swearing by his father's name, so the Prophet Muhammad (peace and blessings be upon him) said: "Indeed, Allah Almighty has forbidden you from this. Do not swear by your forefathers' names. Whoever has to swear, should swear by the name of Allah, otherwise he should remain silent."