The lajnah were asked:
“What is the ruling on someone who swears a lot by Allah without need? He argues that the Prophet (peace be upon him) used to swear a lot by Allah saying: “By the One in Whose Hand is the soul of Muhammad” without anyone asking him to swear. He also argues that Allah (Exalted be He) swears by many of His created things and swears by His Self (Glorified and Exalted be He) in the Qur’an without there being a need for that.”
“Repeatedly swearing by Allah about worldly matters is Makruh (disliked), especially when there is no need for it. This is based on the general meaning of the Ayah (Qur’anic verse) in which Allah (Exalted be He) says: And protect your oaths (i.e. do not swear much). Also, repeated swearing may lead to belittling the Name of Allah (Exalted be He).
The Muslim is required to swear by Allah (Exalted be He) only for the purpose of assuring other people about something, removing any doubt they may have regarding it, or encouraging them to believe what they say to be true. That was the regular practice of the Prophet (peace be upon him).
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.” End quote. [Reference]
Faisal Ibn Abdul Qaadir Ibn Hassan