ENOfficial
It was narrated from Sa`d bin ʼUbaidah, from Ibn ‘Umar, that `Umar said: No, by my father. The Messenger of Allah (ﷺ) said: “Stop it! whoever swears by anything other than Allah has committed an act of shirk.`
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو سَعِيدٍ، حَدَّثَنَا إِسْرَائِيلُ، حَدَّثَنَا سَعِيدُ بْنُ مَسْرُوقٍ، عَنْ سَعْدِ بْنِ عُبَيْدَةَ، عَنِ ابْنِ عُمَرَ، رَضِيَ اللَّهُ عَنْهُ عَنْ عُمَرَ، أَنَّهُ قَالَ لَا وَأَبِي فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَهْ إِنَّهُ مَنْ حَلَفَ بِشَيْءٍ دُونَ اللَّهِ فَقَدْ أَشْرَكَ.
sunnah.com