In this portion, from 58:14, Isaiah is sharing G-d's words.
Call with a full voice, do not spare, like a shofar raise your voice and relate to My people their transgression, and to the house of Jacob their sins. Yet they seek Me daily and they wish to know My ways, like a nation that performed righteousness and did not forsake the ordinance of its G-d: they ask Me ordinances of righteousness; they desire nearness to G-d.And the people ask: "Why have we fasted, and You did not see; we have afflicted our soul and You do not know?" And HaShem answers with a question about how we fast and why we fast.
Behold, for quarrel and strife you fast, and to strike with a fist of wickedness. Do not fast like this day, to make your voice heard on high. Will such be the fast I will choose, a day of man's afflicting his soul? Is it to bend his head like a fishhook and spread out sackcloth and ashes? Will you call this a fast and an acceptable day to the Lord? Is this not the fast I will choose? To undo the fetters of wickedness, to untie the bands of perverseness, and to let out the oppressed free, and all perverseness you shall eliminate. Is it not to share your bread with the hungry, and moaning poor you shall bring home; when you see a naked one, you shall clothe him, and from your flesh you shall not hide?HaShem says not to bow your head and afflict yourself so much as to open your eyes to the true reason we fast, to acknowledge the wickedness and neglect of our people that we pursue day in and day out.
Then your light shall break forth as the dawn, and your healing shall quickly sprout, and your righteousness shall go before you; the glory of the Lord shall gather you in. Then you shall call and the Lord shall answer, you shall cry and He shall say, "Here I am," if you remove perverseness from your midst, putting forth the finger and speaking wickedness. And you draw out your soul to the hungry, and an afflicted soul you sate, then your light shall shine in the darkness, and your darkness shall be like noon. And the Lord shall always lead you, and He shall satisfy your soul in drought, and strengthen your bones; and you shall be like a well-watered garden and like a spring of water whose water does not fail.
And this part I really like, because it says exactly what we need to do; HaShem doesn't mince words. He's not mealymouthed about what is expected of us.
And [those coming] from you shall build ancient ruins, foundations of generations you shall erect, and you shall be called the repairer of the breaches, restorer of the paths, to dwell in. If you restrain your foot because of the Sabbath, from performing your affairs on My holy day, and you call the Sabbath a delight, the holy of the Lord honored, and you honor it by not doing your wonted ways, by not pursuing your affairs and speaking words. Then, you shall delight with the Lord, and I will cause you to ride on the high places of the land, and I will give you to eat the heritage of Jacob your father, for the mouth of the Lord has spoken.
It's easy as pie. So often we look to fast days as a means of pain and suffering for our own souls, for our own being. But the truth is that Yom Kippur and its fast are a means of taking our inward obsession outward and to acknowledge the indifference we have to those around us, to the hungry and empty souls that need to be sated, to observe the Sabbath and to make for ourselves a path of repair.
I want to wish you all a tzom qal (easy fast), which doesn't mean I hope it's a walk in the park for you, but that I wish that you all have come to a point of inner reflection over these Days of Awe so that when it comes to standing before HaShem and asking to be sealed in the book of life that it means something and that it is more than mere words and wishes, that it is based on introspection and action, so that for HaShem it is easy -- easy to seal you eternally in the Book of Life and to the House of Jacob.