Heres a few where we could probably weave in between various parts to show something of what they were doing, what God chose and what Jesus said concerning it.
Theres a couple verses before this one, but to this point here he sais
Isaiah 58:5 Is it such a fast that I have chosen? a day for a man to afflict his soul? is it to bow down his head as a bulrush, and to spread sackcloth and ashes under him? wilt thou call this a fast, and an acceptable day to the LORD?
Similarly Jesus says,
Mat 6:16 Moreover when ye fast, be not, as the hypocrites, of a sad countenance:for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward.
Then he speaks of their own fasting
Mat 6:17 But thou, when thou fastest, anoint thine head, and wash thy face;
Mat 16:18 That thou appear not unto men to fast, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly.
Which His disciples (at the time) did not appear to be fasting given the question posed to Jesus in Mark 2:18-19
Then in Isaiah speaks of the fast he had chosen
Isaiah 58:6 Is not this the fast that I have chosen? to loose the bands of wickedness,to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke?
Iniquities are also shown as a heavy burden
Psalm 38:4 For mine iniquities are gone over mine head: as an heavy burden they are too heavy for me
Jesus was both healing people and forgiving their iniquities
Luke 13:16 And ought not this woman, being a daughter of Abraham, whom Satan hath bound, lo, these eighteen years,be loosed from this bond on the sabbath day?
To loose the bands of wickedness,
Even as we see here,
Acts 10:38 How God anointed Jesus of Nazareth with the Holy Ghost and with power:who went about doing good, and healing allthat were oppressed of the devil; for God was with him.
Thus, to let the oppressed go free
Burdens breaking yokes can be shown
Isaiah 58:6 Is not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke?
The undoing and bearing one another burdens,
Gal 6:2 Bear ye one another's burdens, and so fulfil the law of Christ.
Even Moses is shown as a yoke, and you can see it beginning to be added in Acts
And breaking every yoke, could be inclusive of this one
Acts 15:10 Now therefore why tempt ye God, to put a yoke upon the neck of the disciples, which neither our fathers nor we were able to bear?
And we lay upon you no greater burden...
Acst 15:28 For it seemed good to the Holy Ghost, and to us, to lay upon you no greater burden than these necessary things;
The apostles were breaking off yokes and burdens in that way, where Jesus speaks of the other binding up burdens on others.
Luke 11: 35 Then answered one of the lawyers, and said unto him, Master, thus saying thou reproachest us also.
Luke 11:36 And he said, Woe unto you also, ye lawyers! for ye lade men with burdens grievous to be borne, and ye yourselves touch not the burdens with one of your fingers.
Whereas again,
Gal 6:2 Bear ye one another's burdens, and so fulfil the law of Christ.
Isaiah continues in respects to the fast, saying also
Isaiah 58:7 Is it not to deal thy bread to the hungry, and that thou bring the poor that are cast out to thy house? when thou seest the naked, (James 2:15) that thou cover him; and that thou hide not thyself from thine own flesh?
If you back up, it shows fasting for something (which is not good)
Isaiah 58:4 Behold, ye fast for strife and debate, and to smite with the fist of wickedness: ye shall not fast as ye do this day, to make your voice to be heard on high.
That fast wont get you heard on high, Paul said he was in fastings often.
I do find getting caught up in the things of God, by seeking him (first) that you dont even think of food. In that your thoughts become clearer and His presence magnified.
I have to return to this one, but it seems to show, both from food, and what they did (that he wasnt approving of) and also what he sought of them to do.