(314) Chapter: Prohibition of Swearing in the name of anything besides Allah

Ibn 'Umar (May Allah be pleased with them) said:
I heard a man saying: "No, by the Ka'bah." I admonished him: "Do not swear by any thing besides Allah, for I heard the Messenger of Allah (ﷺ) saying, 'He who swears by anyone or anything other than Allah, has indeed committed an act of Kufr or Shirk'."

[At- Tirmidhi].

[Some 'Ulama' are of the opinion that the words of the Prophet (ﷺ) that "He who swears by anyone or anything other than Allah has indeed committed an act of Kufr or Shirk," are in the nature of extreme admonition. And in fact, it is not Shirk. The same applies to the saying of the Prophet (ﷺ), who said, "showing off is Shirk."]

Commentary: Imam An-Nawawi has regarded the saying "showing off is Shirk'' as Hadith is not narrated in these words. It is, however, true that what the Prophet (PBUH) has stated about the evil and sinfulness of showing off implies that it is also a (minor) Shirk. For instance he stated that "He who kept fast or offered Salat for mere show, has indeed committed Shirk.'' In any case, to take oath of anyone other than Allah is strictly forbidden. It is, therefore, necessary to abstain from swearing by other than Allah. Unfortunately, such oaths are very common and people do not realize that they are prohibited and unlawful.