Vv. 1-5 Just as in the first chapter of Isaiah, we have turned to the idea of hypocrisy; that the people who were supposed to be devoted to God and their neighbors have instead proven themselves to be hypocrites. They daily acted religiously without any sort of connection to the God they claimed to worship. God calls out their fasting; that they fasted not for righteousness sake but rather for their own gain.

Vv. 6-12 The fast the Lord chooses is one in which we take responsibility for our actions and our faith. In this fast we find that we gain freedom not to do our own will, but instead learn the will of the Father. And what is the Father’s will? To pour ourselves out for those in need. In other words, fasting fills us with the Spirit that we may in turn pour ourselves out to be taken in by the needy. Fasting is a voluntary act of affliction in which God intends to use so we may end the involuntary affliction of others. For those who fast in this way, God will allow us to shine, sharing in his glory!

Vv. 13-14 The chapter on fasting ends with the understanding that after a time of fasting comes a time of feast. This feast comes with the observance of the Sabbath. The full idea of the Sabbath is explored here: not only is it a day, but it is a life filled with the rest that was promised to Jacob. This is to be fulfilled by Jesus, that rest is given now that we live not under the burden of man or the law but under the merciful yoke of Christ.