Is it acceptable for a Christian to live on earnings derived from exchange rate fluctuations?

Question:

What is your opinion about the fact that a believer lives on earnings derived from exchange rate fluctuations (to buy foreign currency with a lower price and sell it with a more advantageous one)? Or from the loans bearing interest and lent to others with a higher bearing interest?

As far as I know and understand, this is how banks work and have earnings. I think for a Christian this occupation is not so right because it gives opportunity for many words, suspicions and accusations and in the Scripture it is written:

He who steals must steal no longer; but rather he must labor, performing with his own hands what is good, so that he will have something to share withone who has need. (Ephesians 4:28)(NASB)

I did not put this verse to show that he who practices this steals, but only to show that God teaches us to work on something good. It is also written in the Bible that we should:

make it your ambitionto lead a quiet life andattend to your own business andwork with your hands, just as we commanded you. (1 Thessalonians 4:11)(NASB)

This text does not refer that you have to work only in the field, or with the lathe, or have any other job where you work directly with your hands only, but it refers to a job where you really work and not just profit from others, without working. But when someone takes a loan bearing interest to give it to another one with a higher bearing interest it already looks like speculation and it is neither a work with your hands nor a good job. He who does so does not think how to perform something to share with the one who has need, but conversely, how to rob him 10 times and this is ugly in the sight of the LORD. And then, people who do so, will not lead a quiet life, because there is always someone who can not return the money to him and because of this he will not be able to return those from whom he borrowed, the interest rate increases and he can not sleep at night, then he starts to be like a fugitive and eventually one day his wealth is confiscated or seized. Will his Christian name suffer? Of course.

A good and true Christian will always think at and seek his neighbor’s good and through everything he does he will try to tell people about the salvation in Christ, so that all people who know and meet him may be saved and he will not give any opportunity to anyone to be offended.

I invite readers to comment on this topic or to share their experiences if they had any experience with such people.

Translated by Felicia Rotaru