The first idea comes from the very first chapter of Isaiah. Before we jump in, here's a brief summary of the book:
Isaiah 1-39 is Isaiah's warning to Israel that they need to turn back to God (more information to come) or else their nation will be destroyed. God was right when he called Isaiah in chapter 6 when he tells Isaiah that they will listen, but never hear his words and turn and be healed. In other words, they were so far gone that when they heard the rebuke for their actions, they weren't even able to receive it.
Isaiah 40-55 was likely written by Isaiah's disciples, some 150 years later after Israel has been taken into Babylonian exile, promising that God will come back and lead them back to Jerusalem and it will be a city of peace & justice for all nations.
Isaiah 55-66 is a more developed picture of this new Jerusalem.
Through Isaiah, God makes several accusations against Israel. One of these accusations is that they keep turning to political ideas and military alliances for their hope rather than God (Am I saying that they were wrong to put their hope in the strength of their military and their government instead of God? Yes. Yes I am). One other main theme of an accusation can be found is Isaiah 1:
When you spread out your hands in prayer,
I hide my eyes from you;
even when you offer many prayers,
I am not listening.
Your hands are full of blood!
Wash and make yourselves clean.
Take your evil deeds out of my sight;
stop doing wrong.
Learn to do right; seek justice.
Defend the oppressed.
Take up the cause of the fatherless;
plead the case of the widow. (Isaiah 1:15-17)
Although the people kept up many of their religious practices, they weren't pleasing to God because they weren't taking care of the poor and oppressed. Some scholars explain that the people, when they were owed a debt that the person could not pay back, they would take them to court. If they still could not pay off the debt, they (along with their family) would be sold into slavery. This was specifically troubling because they were doing this to people who were already poor and oppressed.
They were using the justice system, but were not living out justice. They weren't acting illegally, but they were not living out how God intended for them to live in community.
What these words from Isaiah say to us is this: When we don't defend the oppressed and provide for the powerless, we not only rob them of justice. We also put a barrier up in our own relationship with God.
Jesus is faced with a similar issue in the New Testament. Consider the pharisees who, although they were not priests, were voluntarily living by the holiness code developed for Levitical priests. They believed that if they lived to the letter of the law, God would intervene on their behalf and drive Rome from their land. Their land, which was the Promised Land guaranteed by God in the Old Testament, was a material reality that symbolized their relationship with God. It was so important to the pharisees to be able to live freely in the land that they tried push everyone to live out the Levitical code. Those who didn't - tax collectors, prostitutes and any other 'sinner' - were ostracized from the community. To converse with them, or especially to eat with them, would contaminate a pharisee's holiness and make him unclean.
This is why the pharisees were astounded when Jesus and his disciples voluntarily ate with these people. The pharisees, whose motives and actions flowed from holiness and a desire to be in right relationship with God, could not believe that Jesus was God's anointed one when gave up the holiness law to eat with the oppressed. Jesus was jeopardizing their perception of the only chance they had to get God to move.
Just like in Isaiah, the pharisees not only oppressed people with practices, but also damaged their own relationship with God by not caring for these people.
I do not believe it's too far to suggest that we can learn something about racism from these stories. Racism, our perspective and actions that make certain ethnicities lack value or opportunities, is our modern day expression of oppression in the United States. When we do not defend the people from whom our communities and systems have removed some degree of power, we are continuing at best (and helping at worst) that oppression continue. While we may not be liable in the justice system for hate crimes or slavery, we are not seeking justice for people around us.
When we see that injustice is happening, but do not take action to to "Defend the oppressed/Take up the cause of the fatherless; please the case of the widow," it is our own relationship with God that takes the hit. We cannot both knowingly let injustice continue and genuinely seek God simultaneously.
I don't have time to tell you of all my examples working with families in Kansas City, Kansas. Stories of parents without college education who work long hours to provide for their families at dead-end, low paying jobs. Their kids, without their parents at home because of their work hours, grow up barely making it in school and without academic or emotional support at home. Eventually, if they're lucky, they graduate high school, but college was never even mentioned around their home. They have to go to work to pay the bills. These young adults have never heard of a checking account or a savings account, because they're used to living pay check to pay check. There was no savings. If they want a car, they might have to buy it from a "buy here, pay here" place with 17% interest on their loans. If they lose their job or get hit with an unexpected payment, they may find themselves at a title loan company, either losing their car or paying even more interest. This is only just barely scratching the surface.
These people are the oppressed. Telling them to "manage their money" or "move somewhere else' are not helpful suggestions. They don't have money to manage, and they definitely don't have the motivation to move away from their families and community - the only support they have. There's not education (either formal or life-lessons), there is not capital, and there are not social connections that is passed from one generation to the next. These families need someone to defend them.
Did you know that almost half of all black children in the United States live below the poverty line (less than 15% of white children do).
Jesus himself quotes the prophet Isaiah in his first public ministry, according to the Gospel of Luke. He says:
"The Spirit of the Lord is on me,
because he has anointed me
to proclaim good news to the poor.
He has sent me to proclaim freedom for prisoners
and recovery of sight for the blind,
to set the oppressed free,
to proclaim the year of the Lord's favor." (Luke 4:18-19)
This was the outline for Jesus' ministry. When the Word became Flesh (John 1:14), the rule and reign of God broke into our world and began setting things right. If we want to continue to see this picture of the Kingdom of God develop in our world, a picture where the poor get to hear good news and the oppressed are set free, we have to continue to challenge our own stereotypes and take action to bring real justice into our world.