REST
The spiritual truth about fasting is best represented in the concept of rest. Fasting conveys the idea of going without something like food, water and sex that feed the body and arouse discomfort when the body goes without them for an extended period of time. This is exactly the kind of consequence that religious people experience when they try to go without practicing religion. And that is exactly why they need to fast/rest from religion.
Having built up a toxic dependence on religion, religious people don’t feel quite right unless they get their daily, weekly, or seasonal dose of religion. In fact, the Bible says that religious people who don’t do their religious duties will be bothered in their conscience because religious gifts and sacrifices cannot make worshipers perfect in conscience. And if they don’t worry about their relationship to God, they will worry that their fellow religionists will wonder if they are backsliding. These are powerful, guilt-producing influences that keep people devoted to religious activity. Thus people never get to the point that they are confident that they have done everything necessary to get to heaven after they die. And for lack of such confidence, they are enslaved to religion. The simple remedy for this condition is rest, or fasting, from religion.
Some deeply religious people might try to ease into resting/fasting, because they do not want to draw attention to themselves by being absent from religious activities. This strategy is understandable, of course, because the toxicity of religion predicts that people will want to keep doing it.
The big problem is fear of man. If people who might want to quit religion are afraid of what people will say, they do not trust what God has said about fearing man and trusting him. The truth is that anyone who fears man and practices religion as a way of earning the praise of men does not fear God. They fear rejection from men more than they fear rejection from God. It is that black and white. Thus, people who want to ease into resting/fasting from religion, rather than doing cold turkey, are not ready for New Covenant life. Because they love their religious life they hang onto it. If that is what they want, that is what God allows them to have. Having made that choice, they must spend more time in the wilderness of legalistic religion.
The cold turkey strategy is best because no man can serve two masters, and because a casual approach does not line up with loving God with all of our heart, mind, soul and strength. Furthermore, because religion is idolatry, God, being jealous, does not tolerate even a little bit of idolatry.
God makes the point about a quick and decisive move away from religion when he says that failure to enter into his rest (i.e. fast from religion) today is the result of a hardened heart. Because God does not strive with man forever, man should be careful that he does not test God’s patience by being slow to quit religion.