امام علی (ع) می فرماید
روزه قلب بهتر از روزه زبان است و روزه زبان بهتر از روزه شکم است. غرر الحکم، ج ۱ ص ۴۱۷، ح
The fasting of the heart is better than the fasting of the tongue, and the tongue’s fast is better than that of the stomach
The fast of the stomach refers to the common fasting, the zahiri (ظاهری) aspect to fasting where one doesn’t eat or drink from sunrise to sunset. The general definition of fasting for example in the oxford dictionary is to abstain from food. Fasting is meant to bring us closer to our God by keeping us away from the things that take us away from him (food in general does not take us away from Allah but it can reach that point where one’s life revolves around food and pleasing the stomach). The act of Fasting should be used to keep us aware of our actions. Anyone can keep themselves from eating, but not anyone can keep their mouths under control (speak only when needed) let alone their heart.
As Imam Ali has said:
امام علی علیه السلام : مراقب افکارت باش که گفتارت می شود، مراقب گفتارت باش که رفتارت می شود، مراقب رفتارت باش که عادتت می شود،مراقب عادتت باش که شخصیتت می شود، مراقب شخصیتت باش که سرنوشتت می شود
Be wary of your thoughts for they become your words, Be wary of your words for they become your Actions, Be wary of your Actions for they become your Habits, Be wary of your habits for they become your Character, Be wary of your Character for it becomes your fate.
This shows that through each of these stages we still have hope of correcting ourselves if we are being distracted by this world but at the same time we can see that the source is our thoughts. If we can correct our hearts, our mouths will be under control. So when Imam Ali says that the heart’s fast is better than the mouth’s and the stomach’s, it means that the heart is what controls everything else and it’s importance is understood.
In the first hadith, the heart’s fast refers to many things for example our thoughts, desires, jealousy, … or any other batini (باطنی) aspect to fasting. Being able to control one’s desires is a very difficult task which not many succeed, in other words reaching that stage where you have near complete Self-Control. According to this hadith, what we allow our hearts to do determines our fate.