Allah says in the Qur’an, “O you who believe, fasting has been enjoined upon you as it was enjoined on nations before you so that you may nurture taqwa (mindfulness of Allah).” (Qur’an:2: 183).

The Qur’anic statement can be readily confirmed even by a casual reading of the Bible: Let me cite here some verses from the Bible:

New International Version

“Moses was there with the LORD forty days and forty nights without eating bread or drinking water. And he wrote on the tablets the words of the covenant–the Ten Commandments.”

Jesus also fasted for 40 days and 40 nights in the desert – this is commonly known as the Temptation of Christ.

Here is another reference from the Bible (New International Version):

“Then Jesus was led by the Spirit into the wilderness to be tempteda by the devil. After fasting forty days and forty nights, he was hungry. The tempter came to him and said, “If you are the Son of God, tell these stones to become bread.”

Since Jesus came to a milieu where religious rituals had been reduced into mechanical legalistic acts, his main focus was on directing the attention  of the believers to embrace the true spirit of fasting; hence we hear him preach to those who observe the fast not to make show of their actions; rather consider fasting as a means of pleasing God: Therefore, we read in Mathew:

“But when you fast, put oil on your head and wash your face, so that it will not be obvious to men that you are fasting, but only to your Father, who is unseen; and your Father, who sees what is done in secret, will reward you” (Matthew 6:17-18).

This is not different from what the Prophet (peace be upon him) said, “Allah says: Fasting is for Me (it is between Me and My servant); I am the One who determines the rewards for it.”