In some other religions, believers have fast as a part of their ibadat (worship). In the case of Islam, why do Muslims have fast? What is the purpose of fast from the perspective of Islam? Is it for learning to restrain yourself, or does it have any other aim?
In Islam, ultimately, any and all forms of worship are because God told us to worship him this way. Sometimes He told us more, showed us the extra benefits, but that's just detail.
Now that being said, there are many benefits to fasting, and I'll list some in no particular order:
- Earning a great reward from God: There's a narration(Hadeeth) from Prophet Muhammad that promises forgiveness of all sins a person has committed if they fast Ramadan with sincerity. Optional fasts bring you further away from Hell a distance of 70 years.
Self-restraint: It teaches you to control yourself, rather than let your desires control you.
Surat Al-Baqarah 2:183
O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous -
Emphasizing sincerity: Most, if not all, other acts of worship have outwards signs(praying, Hajj, etc.) But fasting is internal and only you and God know whether you are fasting or not.
Appreciating what you have: Speaking from personal experience, you don't know the value of that morning cup of coffee, or that snack in the middle of the day, until you can't have it for a month. Hopefully you learn to appreciate it and appreciate the plight of those who have to do without.
Community bonding: There's great emphasis in Ramadan on praying at the masjid, breaking fast with the community, and being with each other. It brings the community closer together and fosters better bonds.
Health benefits: Fasting has many documented health benefits as well.
Other than its spiritual aspects such as God desires and expects His followers to fast, fasting Affects our physical, mental, emotional aspects:
rest the digestive system
allow for cleansing and detoxification of the body
create a break in eating patterns, while shining a spotlight on them
promote greater mental clarity
cleanse and heal "stuck" emotional patterns
lead to a feeling of physical lightness, increasing energy level
promote an inner stillness, enhancing spiritual connection
As to its spiritual aspects, it helps us to maintain a close relationship with God. It helps us to think about ourselves and our life more focused and gives you greater freedom, flexibility, and energy to get done the things that are important to you. It's a short while of difference that we experience every year. A faster would not commit a crime and there's a weird feelings that makes you think of yourself as a good person.
The thing about fasting is, We all need variety and we need time to think about our lives among our busy moments. Fasting gives us the opportunity and it really feels good at the end when you've done what you must have.
Imam Ali (peace be upon him) mentions in his Nahj al-Balaghah about fasting that fasting shows that all people are equal. Reach people understands poor people's condition better and they'll be encouraged to help people from lower economic status.
The prophet Muhammad (peace be upon him) said:
The stomach is home to all pain and fasting is the highest remedy.
It doesn't end here, there's already a branch of study on fasting and the philosophical reasons behind it.