There are many hadith which tell us about the rewards of fasting. There is no such reward for any other religious act. But there are also many hadith which say that some people's fasting is nothing. One of the hadith is: رُبَّ صَائِمٍ لَيْسَ لَهُ مِنْ صِيَامِهِ إِلَّا الْجُوعُ وَالْعَطَشُ (Musnad al-Shihab al-Qudhayi 1424) Why are there two different kinds of hadith?

There are two forms of fasting. One is fasting with spirit and the other is fasting without spirit. If the spirit of fasting exists, then fasting is genuine. If fasting is devoid of spirit, then it would only be a form. It would have no value in God's eyes. This is why there are two kinds of hadith. As far as form is concerned, every year there is discussion on the form of fasting in mosques, madrasas and gatherings. They all focus on the reward gained by observing the form of fasting. But the significance of fasting is not in its form. Its real significance is in its spirit.

What is the spirit? According to a hadith: مَنْ لَمْ يَدَعْ قَوْلَ الزُّورِ وَالعَمَلَ بِهِ، فَلَيْسَ لِلَّهِ حَاجَةٌ فِي أَنْ يَدَعَ طَعَامَهُ وَشَرَابَهُ (Sahih al-Bukhari 1903) This is a very strongly-worded hadith. If a person remains hungry and thirsty the whole day, but does not leave the culture of lying, then his fasting is nothing in God's eyes. The culture of lying can be present in individual life and also community life. One's life pattern can either be on the culture of truthfulness or falsehood.

If you follow the culture of lying in your life, then even your fasting has no value in God's eyes. During fasting, abstaining from food and water are symbolic acts. When a person leaves food and water, he pledges to leave everything which God dislikes. Only then his fasting is of any value.