It is narrated from the beloved daughter of the Prophet of Islam (PBUH), Lady Fatimah Zahra (SA) who said:

A fasting person who does not protect his/her own tongue, ears, eyes and other body parts from sins, as well as bad and inappropriate actions; what does such a person want to do with fasting and what is the benefit of such fasting [1]?

[1] Beharul Anwaar, Vol. 93, Page 295.

Source:en.shafaqna.com