Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with this chain of narration (it is narrated from Sayyiduna Ibn Umar, may Allah be pleased with them both) that the Messenger of Allah, peace and blessings be upon him, saw: Sayyiduna Umar bin Khattab, may Allah be pleased with him, while traveling in a caravan, swearing by his father. So the Messenger of Allah, peace and blessings be upon him, said: "Allah forbids you from swearing by your parents, so whoever wants to swear, let him swear by Allah or remain silent."