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 SWT or otherwise keep quiet."

Bukhari Vol. 8 : No. 129