Our sermon this past week, from Isaiah 58, centered on a lengthy discussion of fasting—its purpose and nature. In many ways, it is an unusual passage. When it comes to the spirituality of the Old Testament—that is, its understanding of the nature and practice of worship—there are very few places that “go beneath the surface” in the way this passage does.
We can divide spiritual practices in the Old Testament into communal and individual categories. In the Torah—especially Leviticus and Deuteronomy—the communal worship of the Old Testament church is laid out in extensive detail. Worship in Israel was public and external: a matter of offering and sharing in sacrifices, as well as gathering as a community for regular public worship.
What constituted the private worship of individuals in the Old Testament? This is less clear. There are no instructions regarding private worship in the Torah. Practices like prayer and musical praise are present, but not private. There was no conception of a “personal relationship with God”—the relationship was conceived communally. When worship regulations descend to the level of the individual, they are about purity, not worship.
Fasting is neither commanded nor described in detail in the Old Testament—in fact, it is sometimes difficult to fully understand what fasting even entailed. The first mention of a person fasting in the Scriptures is actually quite late. It occurs when David attempts to hold back the judgment of God for his adultery and seeks to preserve the life of his infant son. The second mention is even more curious: when Jezebel devises a plan for Ahab to rob Naboth of the vineyard he covets, it involves declaring a fast. There are a few mentions of fasts in the narratives of the kingdom of Israel, but again—these are public events, proclaimed by the king and joined in by all the people. Fasting, in these texts, seems to be an expression of repentance, mourning, and humbling. Ezra proclaims a fast to seek from the Lord a safe journey home. Jehoshaphat proclaims a fast when the enemies of the Lord invade the land.
However, these relatively rare and brief mentions of fasting in the Old Testament should not lead us to conclude that fasting was rare or unimportant to God. Isaiah 58 makes this clear—it assumes that fasting is an old and widely practiced tradition. The nation clearly fasts regularly, enough so that even in days of wickedness, when the worship of God is greatly degraded, they still fast whenever trouble strikes the land. This is the purpose of Isaiah’s interrogation of fasting—if the practice weren’t widely understood in its public meaning, the chapter would be meaningless.
In my sermon, I suggested that fasting is an instinctive principle of religion, generated by an innate religious impulse that all people share by nature and which is consistently implied in the Scriptures. All religious peoples fast in some way. What’s important is not whether we fast, but how we fast. Fasting is not commanded, but it seems clear from the Scriptures that it was a regular practice of the people of God.
This is also implied in the New Testament when Jesus talks about fasting. As many people have pointed out, in the Sermon on the Mount, Jesus says “when you fast,” not “if you fast.” Fasting is in the background—a natural part of communal worship. The danger of the Pharisees is that they have over-personalized the fast and turned it into a matter of heroic devotion; they want to be honored by others because of their fasting. They have lost the anonymizing aspect of communal worship, in which we do things as a people and participate together. The critique of fasting, as noted in Isaiah 58, is that it is joined with communal injustice and a society degraded by sin. The community should fast together even as it is constructing a just society. These practices reinforce and support each other and have value because of how they work together.