An excellent excerpt on how fasting, journaling, and other means of spiritual growth and exercise can just as easily become a means of legalism and pride.
How self-deceived we humans are when it comes to matters religious. So many things that start off as incentives to repentance and godliness develop into vicious idols. What starts as an aid to holiness ends up as the triple trap of legalism, self-righteousness, and superstition. So it was with the bronze snake in the wilderness. Although it was ordered and used by God (Num. 21:4–9), it became such a religious nonsense in later times that Hezekiah destroyed it (2 Kings 18:4).
So it sometimes is with other forms of religious observance or spiritual discipline. One may with fine purpose and good reason start “journaling” as a discipline that breeds honesty and self-examination, but it can easily slide into the triple trap: in your mind you so establish journaling as the clearest evidence of personal growth and loyalty to Christ that you look down your nose at those who do not commit themselves to the same discipline, and pat yourself on the back every day that you maintain the practice (legalism); you begin to think that only the most mature saints keep spiritual journals, so you qualify—and you know quite a few who do not (self-righteousness); (c) you begin to think that there is something in the act itself, or in the paper, or in the writing, that is a necessary means of grace, a special channel of divine pleasure or truth (superstition). That is the time to throw away your journal.
Clearly, fasting can become a similar sort of trap. The first five verses of Isaiah 58 expose and condemn the wrong kind of fast, while verses 6–12 describe the kind of fast that pleases God. The first is bound up with hypocrisy. People maintain their fasts, but quarrel in the family (58:4). Their fasts do not stop them from exploiting their workers (58:3b). These religious people are getting restless: “We tried fasting,” they say, “and it didn’t work” (58:3). At a superficial level they seem to have a hunger for God and his way (58:2). The truth is that they are beginning to treat the fast as if it were a bit of magic: because I’ve kept the fast, God has to bless me. Such thinking is both terribly sad and terribly evil.
By contrast, the fast that pleases God is marked by genuine repentance (58:6–12). Not only does it turn away from self-indulgence but it actively shares with the poor (58:7), and intentionally strives “to loose the chains of injustice,” “to set the oppressed free and break every yoke” (58:7), to abjure “malicious talk” (58:9). This is the fast that brings God’s blessing (58:8–12).