عَنْ عُمَرَ رَضِيَ اللَّهُ عَنْهُ أَنَّهُ قَالَ لَا وَأَبِي فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ مَهْ إِنَّهُ مَنْ حَلَفَ بِشَيْءٍ دُونِ اللَّهِ فَقَدْ أَشْرَكَ
It is narrated from Sayyiduna Umar (may Allah be pleased with him) that when he swore an oath saying, "No, by my father's oath," the Messenger of Allah (peace and blessings be upon him) said to him: "Stop! Indeed, whoever swears an oath by anything other than Allah has committed shirk."