63. Merits of the Helpers in Madinah (Ansaar) - كتاب مناقب الأنصار
26) Chapter: The days of Pre-Islamic Period of Ignorance
Narrated Ibn `Umar:
The Prophet (ﷺ) 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 (ﷺ) said, "Do not swear by your fathers. "