I noticed in Matthew 6, that right after Jesus gives some instructions on fasting (don't do it in a show-off way), that he talks about some other things that can get out of control in our lives and need to be abstained from.
Imagine a movie about a time before the modern era. Perhaps the first, second, or third century. A man or woman looks for pebbles all day, gathers them, and puts them on display. He or she wakes up each morning and gazes fondly at the pebbles. The person might also have friends that collect pebbles and they compare and muse for hours about the different pebbles they might find or tell stories of the rarest pebbles that others have found.
Jesus had something to say about this kind of thing:
"Stop collecting treasures for your own benefit on earth, where moth and rust eat them and where thieves break in and steal them. Instead, collect treasures for yourselves in heaven, where moth and rust don’t eat them and where thieves don’t break in and steal them. Where your treasure is, there your heart will be also." -Matthew 6:19-21
Fasting from the world means to stop the collecting activities that are not kingdom activities. "On earth" is contrasted with "in heaven". Nothing is wrong with collecting treasure for yourselves, as long as it is heavenly and not earthly treasures. It is very true that, "you can't take it with you".
Everywhere, advertisements are crying out, telling us that we deserve this and that benefit. There are shopping websites and idea websites that we look at for hours, that lead us towards benefiting ourselves with earthly treasures. Some people see shopping as their joy and recreational activity.
We have to corral our desires back to God, back to God's kingdom, back to kingdom activity. Jesus says "stop", because we may have to deny our selves something in order to bring it down to a smaller place in our lives.
“The eye is the lamp of the body. Therefore, if your eye is healthy, your whole body will be full of light. But if your eye is bad, your whole body will be full of darkness. If then the light in you is darkness, how terrible that darkness will be!" -Matthew 6:22-23
Fasting from the world to make way for the kingdom of God in our lives brings up the issue of what we look at. What you gaze upon is what you become. To make way for the kingdom in our lives, we need to be more careful what we look at. Darkness inside a person of the light is a tragic thing.
Are we constantly looking at things, wanting them, lusting for them, coveting other people's things? Is our life marked by discontent or generosity? Are we constantly looking to have, to desire, to want for ourselves; or are we always attentive to what we can give and are we content on earth, while hungrily desiring more of heaven? Cultivate generous eyes. Learn to see how Jesus sees. The Holy Spirit will help you see this way.
"No one can serve two masters. Either you will hate the one and love the other, or you will be loyal to the one and have contempt for the other. You cannot serve God and wealth." -Matthew 6:24
Some of us may need to fast from serving wealth. Is your life centered around making money or serving God? Nothing is wrong with making lots of money and being wealthy. But, is building wealth or building the kingdom your priority? Who do you serve? Has your wallet gotten saved?