Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah
Narrated ‘Umar (Radi-Allahu ‘anhu):
The Prophet (Sallallahu ‘Alaihi Wa Sallam) said, “If anybody has to take an oath, he should swear only by Allah.” The people of Quraish used to swear by their fathers, but the Prophet (Sallallahu ‘Alaihi Wa Sallam) said, “Do not swear by your fathers.”
Bukhari Vol. 5 : No. 177