Isaiah 58:1 Cry aloud, spare not, lift up thy voice like a trumpet, and show my people their transgression, and the house of Jacob their sins.
​ Isa 58:2 Yet they seek me daily, and delight to know my ways, as a nation that did righteousness, and forsook not the ordinance of their God: they ask of me the ordinances of justice; they take delight in approaching to God.

In Isaiah's day people were going through the motions of church, but their hearts were far from God & His commandments. It says they seek me daily AS a nation that did righteousness, but they were not.

Isaiah 58:3 Wherefore have we fasted, say they, and thou seest not? wherefore have we afflicted our soul, and thou takest no knowledge?

They say, "Lord, we have fasted and you don't see. We have humbled our souls and you have not recognized it."

The Lord answers them in the next part of this verse. Behold, in the day of your fast ye find pleasure, and exact all your labours.

Amplified: Behold [O Israel], on the day of your fast [when you should be grieving for your sins], you find profit in your business, and [instead of stopping all work, as the law implies you and your workmen should do] you extort from your hired servants a full amount of labor.

They were not keep God's Laws, but yet they wanted God's blessings. Sounds like church people today doesn't it?
​ I say "church people" because they are not true Christians. True Christians strive everyday to be more like their heavenly Father, and show His love nature.

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.

They were quarreling & fighting (literally) and they thought their prayers were going to be heard. But the Lord told them the kind of fast they should be doing.

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?
This is the kind of fast they were to do.
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?                                                                                               
Isa 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, that thou cover him; and that thou hide not thyself from thine own flesh?
In other words: LOVE GOD & LOVE YOUR NEIGHBOR AS YOURSELF! Then you will fulfill the Law.
Isaiah 58:8 Then shall thy light break forth as the morning, and thine health shall spring forth speedily: and thy righteousness shall go before thee; the glory of the LORD shall be thy rereward.
​ Isa 58:9 Then shalt thou call, and the LORD shall answer; thou shalt cry, and he shall say, Here I am. If thou take away from the midst of thee the yoke, the putting forth of the finger, and speaking vanity;
​Isa 58:10 And if thou draw out thy soul to the hungry, and satisfy the afflicted soul; then shall thy light rise in obscurity, and thy darkness be as the noon day:
​Isa 58:11 And the LORD shall guide thee continually, and satisfy thy soul in drought, and make fat thy bones: and thou shalt be like a watered garden, and like a spring of water, whose waters fail not.
​Isa 58:12 And they that shall be of thee shall build the old waste places: thou shalt raise up the foundations of many generations; and thou shalt be called, The repairer of the breach, The restorer of paths to dwell in.
​Isa 58:13 If thou turn away thy foot from the sabbath, from doing thy pleasure on my holy day; and call the sabbath a delight, the
holy of the LORD, honourable; and shalt honour him, not doing thine own ways, nor finding thine own pleasure, nor speaking thine own words:
​Isa 58:14 Then shalt thou delight thyself in the LORD; and I will cause thee to ride upon the high places of the earth, and feed thee with the heritage of Jacob thy father: for the mouth of the LORD hath spoken it.

The New Century Version says, If you stop making trouble for others, if you stop using cruel words and pointing your finger at others, 10 if you feed those who are hungry and take care of the needs of those who are troubled, then your light will shine in the darkness, and you will be bright like sunshine at noon.
11 The Lord will always lead you. He will satisfy your needs in dry lands and give strength to your bones. You will be like a garden that has much water, like a spring that never runs dry.
12 Your people will rebuild the old cities that are now in ruins; you will rebuild their foundations.
You will be known for repairing the broken places and for rebuilding the roads and houses.

Wow that is awesome! God said, "If you do the right thing, then I will bless you abundantly."
​ Then you shall be the light you are supposed to be. Your healing will come quickly. The Lord will walk before you and His glory shall guard you from behind.
​Then call pray to God and He will answer.
​If we delight ourselves in the Lord we will walk in the heritage of Jacob.