Faith is modifying your thoughts and actions because God exists. God is in Heaven so we cannot see him. So unbelievers claim that faith is blind. Actually in truth, the opposite is true. The lack of faith is spiritual blindness. "Wait, how can this be?” many people will say. Lets do an example. Some atheists(people who have no faith) believe that we're all a product of chance, and morality doesn't actually matter. Another atheist may take the idea that morality doesn't matter and decide it is alright to lie to achieve one's own goals. Lying is a sin. Now you have two atheists that are guilty of sin here: The atheist that is sinning by lying, and his teacher the atheist that said morality doesn't matter. Jesus was referring to the Pharisees when he said this: Mt 15:14 "Don't worry about them! They are blind leaders of the blind; and when one blind man leads another, both fall into a ditch." An atheist that reasons that nothing matters can end up performing any act. This is known as spiritual blindness. Faith is not blind because it uses the light of God to shine on the path.
Faith is not to be confused with belief in God. Sometimes the degree to which you believe in God changes your faith, but they're not exactly synonymous. Faith is the guideline for how you live your life taking into consideration that God is real. If you don't believe God is real, your faith will be nonexistent. If you know God is real, it does not automatically mean you'll live your life with faith. Faith is a choice you have to make when you believe in God.
There are many degrees of faith. A man with a little faith may treat others nice, but take revenge instead of forgiving people that wrong him. A man with great faith may absorb great abuses from others and still forgive them. A man with a little faith thanks God when he is blessed, but questions God's motives when things aren't going well. A man with advanced faith may not indulge in wasting any of his time or money on entertainment because he knows his time and money can be better spent on the poor. Faith is an attribute that pleases the Lord, so having more faith is something that all Christians should strive for.
I personally work on making sure I am a good steward of my money. I rarely buy beer even though I like beer. I know that 20$ spent on beer could be better spent helping people eat who would otherwise starve to death. I see poverty as the #1 issue plaguing the world today. If everyone had enough to eat and drink, we'd not only be a more humanitarian world, but also it would help in other ways. A person who doesn't die of malnutrition can get an education and be a useful member of society.
Jesus alludes that the rich people of this world will be judged with greater severity. Mt 19:24 - Show Context " I repeat: it is much harder for a rich person to enter the Kingdom of God than for a camel to go through the eye of a needle." I speculate the reason he does this is that the rich have it in their power to change this world. Remember the movie Schindler's List? When Oscar Shindler thinks about he could have saved more Jews from extermination by selling his car and pocket watch, he reels in despair. Our present situation is that there are people starving to death in the world, and the only thing they need to save them is money to buy them food. With the economics of supply and demand, there will be enough food for everyone if there was a better distribution of wealth. Socialism is the forced distribution of wages. What we need for the world to be a better place is a personal desire to donate. When you donate, you lose power to achieve your own goals, but you help people from dying. It takes faith to lose personal happiness in order to keep someone else from death. This is what faith is. There are many other examples, but many do boil down on personal sacrifice in order to help your neighbor.