Let's take a look at the different types of fasting in the Bible, because I don't want you to feel overwhelmed by the thought of going without food for days and days. There are types of fasting that don't involve such a radical commitment. The Bible gives examples of many different kinds of fasting. (The terms "normal fast," "partial fast," and "radical fast" which appear below are not Biblical terms. They are entirely of my own making and simply a way to categorize the different fasts we see in the Bible.)
The Normal Fast:
There are very few rules when it comes to fasting. What you do is really between you and the Lord. There is only one fast command in the Bible and that was the fast on the Day of Atonement. This fast was from sunset of one day to sunset of the next (Leviticus 16:29;23:32). Since, people usually don't eat during the night that makes the fast fairly easy, since you can eat again in the evening before retiring to bed. According to the Zondervan Pictorial Encyclopedia of the Bible: "The rabbis ruled that one could not eat a quantity as large as a date on this day...According to the Mishna, Yoma 8:1, on the Day of Atonement it is forbidden to eat, or drink, or bathe, or anoint oneself, or wear sandals, or to indulge in conjugal intercourse" (Zondervan Encyclopedia, vol 2, 502). Of course, this direction is not from the Bible, but perhaps we can look at that as a template for a "normal fast." So in this type of fast the person abstained from food and liquid for a period of one day (from sunset to sunset). This is a normal fast.
The Partial Fast:
In this type of fast, the emphasis is placed on restriction of diet, rather than abstaining completely from eating. Examples are: Daniel, Shadrack, Meshach and Abednego eating only vegetables and drinking only water (Daniel 1:15) and later on when Daniel alone practiced a limited diet for three weeks (Daniel 10:3). Some people would argue that this isn't really a fast at all, but Daniel 10:3 does use the word "mourned" which is a Biblical occasion for fasting (see below) and a common synonym for fasting.
The Radical Fast:
This type of fast is one in which the person refrains from both food and water OR simply food (but not water) for an extended period of time. A radical fast can be harmful to your health and in most cases should not exceed three days. An example of a radical fast can be found with Esther and her household. Esther decided to fast for three days abstaining from both "food and water" both "day and night" (Esther 4:15-16). The rabbi Ezra and the apostle Paul also went without food and water for three days (Ezra 10:6-9; Acts 9:9). David is another example of a radical fast. He went seven days without food (but probably with liquid) as a plea to God to save the life of his child (2 Samuel 12:15-20). Fasts that extend beyond three or seven days can be found in the Bible, but these exceptions were based upon direct guidance from God or a supernatural ability given by God to complete the fast. Examples of these extreme fasts are: Moses (Deuteronomy 9:9-18 and Exodus 34:28); Elijah (1 Kings 19:8); and Jesus (Matthew 4:1-11).
Biblical Principles on Fasting
Fasting is Assumed by the New Testament: When Jesus spoke about fasting, he didn't say if you fast, but "when you fast" (Matthew 6:16). Our Lord assumes that Christians will fast. And from the rest of the books in the New Testament we know that they did.There once was an inappropriate time for fasting though: when our Lord was here on earth. During that time Jesus' disciples never fasted and that seemed unusual to the religious leaders and John the Baptist's friends. "Then the followers of John came to Jesus and said, 'Why do we and the Pharisees often fast for a certain time, but your followers don't?' Jesus answered, 'The friends of the bridegroom are not sad while he is with them. But the time will come when the bridegroom will be taken from them, and then they will fast.'" (Matthew 9:14-15).
Now Jesus is no longer physically present with us. He will not be until His second coming. So until the rapture, our Lord knows there will be times when fasting is an appropriate response. He is not here and because of that there will be spiritual struggle, and tribulation, and a need to fast.
Wealth is not just what you have, but what you are.