Tax collectors came and they asked Him, "Teacher, What should we do?" He said to them, "Collect no more than the amount prescribed for you." Soldiers also asked Him, "and we, what should we do? He said to them, "Do not extort money from any by threats or false accusation, and be satisfied with your wages." Luke 3:13
Plummeting back to earth has been jolting enough after thinking about Marks 78 and 79, when we met Jesus in the air, but Mark 80 sends us to the very core of our earthly existence, i.e. survival by money.
To be totally fair and honest in our profession while being diligent, is to trust that God will help us succeed. Money looks like paper and metal that we trade for food and shelter and all sorts of gratifying things, but it is really more like a thermometer.
Response to the lack of money is as valuable an indicator to God of His child's spiritual development as is response to an abundance of money. Lack of money is a type of fasting that can turn our faces toward God with gratitude for all the beautiful things in life that money can't buy. An abundance of money allows God to clearly see our priorities.
Perhaps it's not love of money, nor need for survival that drives some people to be so bad, but rather the love of power. Bullies, cheats, and thieves have heavy muddied feet that will keep them nailed to this exploding planet earth when it is time for aspiring immortals to enter God's new world as described in Revelation 21.
To hit this Mark is to be Christ-like at work.