Fasting (Isaiah 58:3-9)

The readings for the day are about fasting. In the Gospel, Jesus dismisses John's disciples concern about Jesus' disciples not fasting. A large portion of the First Reading is worth pasting here in full without commentary.

"Why do we fast, and you do not see it?
afflict ourselves, and you take no note of it?"

Lo, on your fast day you carry out your own pursuits,
and drive all your laborers.
Yes, your fast ends in quarreling and fighting,
striking with wicked claw.
Would that today you might fast
so as to make your voice heard on high!
Is this the manner of fasting I wish,
of keeping a day of penance:
That a man bow his head like a reed
and lie in sackcloth and ashes?
Do you call this a fast,
a day acceptable to the LORD?

This, rather, is the fasting that I wish:
releasing those bound unjustly,
untying the thongs of the yoke;
Setting free the oppressed,
breaking every yoke;
Sharing your bread with the hungry,
sheltering the oppressed and the homeless;
Clothing the naked when you see them,
and not turning your back on your own.

Then your light shall break forth like the dawn,
and your wound shall quickly be healed;
Your vindication shall go before you,
and the glory of the LORD shall be your rear guard.
Then you shall call, and the LORD will answer,
you shall cry for help, and he will say: Here I am!

Isaiah 58: 3-9