Shaykh Sālih al-Fawzān said,
Fasting is beloved to Allāh, due to this it is compulsory upon the fasting person to rectify his intention, making his fasting sincerely for Allāh. And he should intend to draw closer to Allāh, with his fasting, whilst being patient with any difficulties he finds in fasting, because fasting is an act of obedience to Allāh. Therefore, upon him is to purify his intention and to be patient.
He should then also know, that fasting isn’t merely refraining from food and drink; rather it is also refraining from everything Allāh has prohibited. He protects his hearing and tongue from that which is prohibited, such as backbiting; slandering and listening to music. And he protects his sight from looking at those things which are prohibited for him. These affairs are prohibited throughout the year, but even more so for the fasting person.
It could be the case that a fasting persons hunger is severe upon him, as is his thirst and tiredness, but he has no reward with Allāh. This is because of his tongue, speaking with that which is prohibited. His eyes looking at that which is prohibited. And his ears listening to that which is prohibited. This person in reality, he didn’t fast (in the complete sense), he merely left off food and drink.
Fasting is a tremendous act of worship, if someone fasts, then indeed he should stay far away from everything which is unsuitable and unbefitting.
A fasting person is similar to the one performing hajj or umrah, they have to leave off some affairs which are permissible. For example eating and drinking in their origin are permissible. However whilst fasting, he abstains from them. And likewise he must stay away from those affairs which are impermissible, whilst fasting and at all other times, but the issue becomes even more severe whilst fasting.
Hence, it is obligatory upon the fasting person to take care of his fast from everything which will affect it negatively.
Abridged and Paraphrased from Shaykh Sālih al-Fawzān’s, Majālis Shahr Ramadhan al-Mubārak pgs 14-16