The timing and era of Isaiah is a question scholars have dealt with in depth with no real consensus. Jewish tradition says that Isaiah died during the reign of Manasseh of Judah and that his career spanned more than 80 years. Evangelical Christianity hold that Isaiah may have prophesied for as much as 64 years (it all depends on when one begins counting). Some scholars believe that Isaiah can be divided up into several parts, some written by the historic Isaiah, others written up to 100 years later as commentary on the original sections. Being aware of the various ways the book has been divided provides a background for the entire work, but in this pericope, the historic prophet Isaiah is writing a poetic reprimand to the people of Israel, not just during one king’s rule, but over a long period of time.
In verse 10, Isaiah equates Israel with the rulers of Sodom and the people of Gomorrah. In Ezekiel 16:49 the prophet says: "'Now this was the sin of your sister Sodom: She and her daughters were arrogant, overfed and unconcerned; they did not help the poor and needy.” While we tend to think of the sin of Sodom being sexual, the Old Testament prophets, Isaiah and Ezekiel, equate the sin of Sodom as being neglect of the poor. In this vein, Isaiah opens up with the comparison of Israel and Sodom and Gomorrah. In verse 11, he continues by discrediting their numerous sacrifices. Zebach is the Hebrew term used here means sacrifices or offering. It is worth noting that sacrifices are always offered up to God. V. 13 uses a different Hebrew noun, minchah, which also means offering, but goes further into the idea of giving--it is from a root meaning to apportion. It would appear the prophet is foreshadowing again the need to apportion, to sacrifice, to give up to the poor and needy before giving up worship to God. The word saba`, translated here as enough, has the poetic connotation of being fed up or sated, which again plays on the idea of having enough to eat. Burnt offerings brings forth the imagery, the smell, of cooking meat. The festivals and feasts mentioned are religious, but all involve more burnt offerings and food.
Then Isaiah becomes very pointed in his critique of Israel’s behavior. He says that their worship is not acceptable to God because they have not feed the poor. God doesn’t hear their prayers. He calls their worship an abomination--detestable. Back in v. 10 Isaiah asks the people to listen to the instructions being given to them and now, after telling them what they have done wrong, he begins to instruct them on proper behavior:
Wash and make yourselves clean
Stop doing wrong
Learn to do right
Defend the oppressed (or Correct the oppressor)
V. 18 is probably the most widely known verse in this pericope. Though, in this context, the red as crimson and scarlet sins serve to reinforce the imagery of the blood, the dam, that is referenced in the blood of the sacrifices and the blood filling the hands of the Israelites. Isaiah will simply not let up; the Israelites are guilty. They are detestable. Their worship is an abomination. They are red with sin and blood and need to wash themselves clean. V. 19 explains how they can do this--by being willing and obedient--while warning that if they resist and rebel there will be punishment. Again, the imagery is of consuming food: willing and obedient=eating the good things of the land; resistance and rebellion=devoured by the sword.
Isaiah is not playing around. He is clear that God is not accepting the worship of, nor hearing the prayers of the people of Israel because they are not feeding the hungry and taking care of the needy. In 2015, the World Food Programme put out a startling statistic: Poor nutrition causes nearly half (45%) of deaths in children under five worldwide - 3.1 million children each year. Specifically, in the United States, the U.S Department of Agriculture reports that 49 million household struggle to obtain enough food to eat in 2014. Nearly 16 million of these are children, who are far more likely to suffer from food insecurity. While 15.9% of Americans live in food-insecure households, 21.6% of children have uncertain access to food. Feeding America, the largest organization in the United States to assist and track hunger and poverty, reports that the highest rates of food insecurity exist in Mississippi (22%), Arkansas(19.9%), Louisiana (17.6), Kentucky(17.5%), Texas (17.2%), Ohio (17.2%), Alabama (16.8%), Missouri (16.8%), North Carolina (16.7%), Oklahoma (16.5%), Tennessee (16.3%), Maine (16.2%), Oregon (16.1%), and Kansas (15.9%). Nazarene Compassionate Ministries works in this area of need, both around the world and here in the United States and Canada through USA/Canada Hunger Relief.
If we as a church are going to present worship to our God, we need to make sure that we are worshiping in a way acceptable to God. According to Isaiah, to be acceptable, we must take care of the hungry and the poor. The church should feed the hungry, not just from headquarters, but on the ground, locally. It all goes back to that great holiness command that Wesley preached: “Love God and love neighbor.” Without doing both parts, we do not fulfill the commandment.
 Historical Dictionary of Prophets in Islam and Judaism, B. M. Wheeler, Appendix II
 http://www.feedingamerica.org/hunger-in-america/impact-of-hunger/hunger-and-poverty/hunger-and-poverty-fact-sheet.htm also look at the interactive map here: http://map.feedingamerica.org/county/2014/overall