Where does the custom of fasting on Eid al-Adha until the sacrifice come from?

It is not a real fast, for the Holy Prophet Muhammad (saw) forbade fasting on Eid al-Adha. Whoever waits in the morning before eating until the sacrifice has been made is following a custom, not an obligation.

Eid al-Adha is a day of joy on which people eat of the sacrificial animals. The hadith above describes it in exactly these terms and says that one should not fast on this day. So when some Muslims eat nothing in the morning until the sacrifice has been made, this is not a prescribed fast. It is a custom with which they begin the festival.

More helpful than asking where this custom comes from is asking why we fast at all when food is available. The answer lies in the belief that God is the Creator of every provision. Everything we have comes from Him, and we may use it only with His permission. When He says stop, we stop. So whoever fasts bears witness that God is the true Owner of everything.

Even a well-trained dog will not take food it sees in its master’s hand before it is given. It waits patiently. Human beings, however, easily forget to whom they owe everything. That is why they are reminded again and again.

This is why fasting is found in every religion, as the verse above says. The forms differ, but fasting itself is present everywhere. Why God prescribed it to peoples in different ways at different times is something we cannot know in every detail.

Fasting in Islam is neither too easy nor too hard. It is strict enough to let one truly feel hunger. In this way one learns to feel for the hungry all over the world and to work so that no one has to go hungry.