Sulaymân b. Mûsâ [d119H] – Allah have mercy on him – said:
When you fast, your hearing and sight should also fast, and your tongue should fast by keeping away from lies; and do not harm your servant. Don’t let the day you fast be the same as the day you don’t fast.
Târîkh Dimishq Vol. 22 p389.
Al-Sawm (fasting) literally means to keep away from something. Fasting of the faculties of hearing and seeing means to keep away from listening to and looking at things that are displeasing to Allah, in the same way that we stay away from food and drink when we are fasting.