Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah
Narrated Ibn ‘Umar (Radi-Allahu ‘anhu):
that he found ‘Umar bin Al-Khattab in a group of people and he was swearing by his father. So Allah’s Apostle (Sallallahu ‘Alaihi Wa Sallam) called them, saying, “Verily! Allah forbids you to swear by your fathers. If one has to take an oath, he should swear by Allah or otherwise keep quiet.”
Bukhari Vol. 8 : No. 129