Usury Is Charging ANY Interest
Bitcoiners are going to have to learn this soon.
Many people believe that usury means charging excessive interest rates. But, it is not. It is charging ANY interest.
It is a mathematical problem.
Such as, if you put 1 ounce of gold in a bank at 4% interest back when Jesus was walking around, today you would have more gold than all the gold in the world.
It is the problem with our currency today, they create the loan out of thin air, but they do not create any currency to pay the interest. And there has never been enough currency to pay back all of the loans. And today, there is probably not enough money to pay off the national debt & interest. And, if there was, we would pay that off, and there would be no currency left.
And this is with an expanding money supply. (well, that is the only reason it has gone on so long)
With bitcoin, it will be a very short while before the interest owed is more than 21 million bitcoin.

Compound Interest Cannot Exist In Nature
The thing closest to a power curve in nature is microorganisms that constantly divide to create more of themselves, as long as there is food available. So, they double and double and double, and then they all die.
Larger multi-celled organisms run into the limits of expansion much quicker. And most have a method of balancing themselves out.
Even low percentage power curves quickly eat up the entire world.
Many "retirement planners" like to say that the stock market grows 10% per year (or 7%, depending on bull or bear) but has it really?
Is CocaCola really 10% bigger than it was last year? Do they sell 10% more Coke products? Did they hire 10% more people? If they haven't, than that 10% increase in stock price is only paper gains. And that is only because of money printing.
If CocaCola can actually increase 10% per year, then how can Pepsi still exist? All of the people, all over the world, should now be drinking Coke. And without the planet's population expanding, there would be no more growth available. Again, the growth is fake. The price of the stock has only gone up because there is more paper in the system.

Money printing (without creating goods that people want) is a sin
Fractional Reserve lent, debt based, fiat currency is extremely damaging to the society that lets it exist. If you print currency without creating goods (that people want!) than you are causing inflation. This is a hidden cost on all people who use the currency.
Such as the stock market going up 10%, that is paid by all the people losing 10% (or more) of their purchasing power. And what is worse, is that those who aren't investing in the stock market also pay. Those in the stock market barely broke even. Those who put their money in a savings account at 3%, lost 7%. And those who aren't investing in the riskiest of assets lost everything.
They say that compound interest is a very powerful force. However a compounded loss is even more destructive. At a 10% real inflation rate, people lose half of their wealth every 7 years. If a person works 50 years (49 = 7 x 7) their original dollars they made is not even worth a penny. Nearly everything they made in their youth is as if they never earned anything.
You know, people bought a house back then for $17,0000, which today is valued at $1,000,000. If they instead saved that $17,000, they couldn't even afford rent for a year today.
This is, supposedly the stuff that bitcoin saves us from, but only if we get rid of all interest.

Why we cannot charge interest on bitcoin loans
The problem is easier to see if we include the entire pie (economy).
If we just look at a single person, and they want to borrow 10 bitcoin, and are pretty sure they can start a company and make 11 bitcoin to repay the loan and interest, well then you might think that is all ok.
But, if we look at all the people borrowing, we run into a problem where soon, the interest owed is more than 21 million bitcoin. The principal may or may not have been paid, but the interest keeps growing.
And, if you play this game long enough, one person ends up with ALL the bitcoin. (or, are at least owed all the bitcoin) (This is the game the banksters are playing right now. In the end, the house always wins, and so do the banksters, if allowed to exist)
An easier way to visualize this is a knight offers this town some coins, so that they can more easily buy things (instead of just barter). He gives the butcher, baker and candlestick maker 10 coins, and says if they do not pay him back 11 coins in a year, he gets to take all their property.
You should be able to make one more coin, right?
Well, you cannot. There are only 30 coins in existence. There is no way that 33 coins exist after a year, no matter how much they sell. If we stop the economy and take a picture, we will find pictures like 9-9-12, 10-10-10, 9-10-11, 8-11-11 and really it just depends on what time of year the knight comes back who will lose their property.
There is no way to pay for the interest.

And it is the same with bitcoin.
Sure, one person could make more bitcoin and pay back the principal and interest. But, all the people, totalled cannot. When you add interest to a financial system, then you are making it so that the slowest person goes bankrupt. Not because of anything they did, but because there is never enough money in the system
This is why usury means ANY interest, and why usury is so bad.
It is also the reason why the Bible says to forgive loans every seven years.
Now, why would you lend your bitcoin out for 0%? Well, if you lend the bitcoin to build a house, and the builder pays you back, then you have all your bitcoin still, AND the world has another house. The world is richer. Your portion of it, expressed through bitcoin (money) is now worth more.

I agree in part but you are oversimplifying. Inflation definitely plays a part. If a value of a stock goes up 10% and inflation is 3% then real gains are 7%.
Also, the 10% growth is an average. Coke stock is worth about 0.75% less than it was a year ago. But some companies have grown, on average, much greater than 10%/year. Tesla, Microsoft, Apple are a few companies that come to mind.
Also, there's more ways to increase value than pure growth. You can be producing the same amount yet become more efficient for example. I work for a company that develops software for a major food company. Every change they come to us with (which are many every year) is all about increasing efficiency.
Also, as the demand for a fixed quantity asset goes up, its value relative to other things goes up so you end up subdividing it further. The smallest unit of Bitcoin is the Satoshi. Perhaps one day it will be worth $1, in part because the value of the dollar goes down, and in part because the value of Bitcoin goes up.
As for the definition of Usury, it's definition is a little murky. In Christianity, the admonition mostly seems to be against charging interest on a loan to somebody in need. But if you are "rich", does that apply? If I have an apartment but want to buy a house and am changed interest does that fall into that category? I wouldn't think so. But if I'm starving and need money to buy food, then loaning money to me and charging interest would definitely fall into that category.
The reason you might not loan your Bitcoin is risk. You have no guarantee that who you loan the Bitcoin to will be willing or able to pay you back. If you are in the position to give someone a house, fine, do that. There's no need for a loan. If you can't afford to give away a house then you can't afford to loan the money for one without mitigating your risk and that would take having enough to make multiple loans.
Yep, i used to think that way.
And it never worked out mathematically.
I can build a nice house, by myself, in about a year.
So, why does it cost 30 years of someone's life?
Because of usury.
So, is the Fed way better, or is the Amish way better?
Borrow money they print out of thin air (causing inflation) and paying interest (more usury) and buy a house from some builder
or
Get your friends together and build a house, all paid for the moment it is done?
And i don't think i made it clear how much the Fed way actually costs.
If you get a mortgage to buy a house, it may seem good to you on paper, but no one looks at the real costs.
You have just made your children pay more for their house. Inflation + interest really adds up.
AND if you pay your house off, you are insuring that at least one person goes into bankruptcy.
These two are a direct result of your getting a mortgage and usury.
Was it worth it?
I don't have the skills to build my own house. Could I gain those skills? Sure...but I would rather work at something I enjoy more and use the proceeds from that to pay for one. I bought a newly built house with a 30 year mortgage. I paid it off in about 13. It was worth it to me. While I don't like the amount of control the government and the Fed have on money and interest rates, an inflationary money supply isn't necessarily bad within reason (even gold is inflationary...there is always more being dug up and put into circulation), you just have to understand how to use it. And yes, the Fed certainly goes beyond reason. Savings is taxed and debt gets cheaper over time. If you want to "save" then you have to "invest". A fixed pile of fiat currency won't go up in value but property, whether that's ownership in a company or gold or whatever, will inflate with everything else so you won't lose value (to inflation anyway). If you stick your money in a savings account paying 0.01% interest, then you are screwing yourself.
Inflation affect salaries too. Sure, my children may pay more for a house in the future but they will also be making more money. I make a lot more money than my parents who made a lot more money than their parents. Houses today are more expensive relative to salary than they used to be but I believe that's more because they are, on average, much larger and have many more features (some of which are because of increased regulations) than they used to. Government regulation plays a big part in the cost of a house. Just look at California for an extreme example.
Nobody is making anybody get a 30 year mortgage on a house. My grandparents lived in an 850 sq. foot house. Even today, such a house can probably be had pretty cheaply. Buy a mobile home. Rent a cheap apartment. A house that is expensive enough for a 30 year mortgage is a trade-off. Everybody has to judge for themselves if it one worth making. If you want to get together with your friends to build your own houses, nobody is stopping you, right? I mean a mortgage is a choice not a prison sentence. Nobody is making you pay interest...you have to choose to take out a loan. But expecting "free" loans on a large scale is not realistic.
Personally, I hate being in debt. Mostly by this I mean unsecured debt like credit card debt. That's the interest that kills you. That's usury. 6% on a house can be a lot but given the equity you typically build, it isn't so bad. I don't feel so bad about a car payment or a house payment. As long as you make reasonable choices, you can always get out of that by selling your house or your car if you really need to.
So no, I don't particularly like the Fed way but the lack of the Fed and going back to a gold standard wouldn't make mortgages and interest go away.
The children of today are making much less that people in 1971, adjusted for inflation.
If you adjust for real inflation (shadowstats.com) then they make much less. And the house, adjusted for inflation, is much more.
At minimum, salaries lag behind inflation. And this is compounded.