I reckon the ancient church had it about right with the law of no more than 1% interest per month.
The concept of people just lending money as a gesture of goodwill, without any expectation of getting it back again, never mind with interest, is a nice concept, but in reality it's just going to mean that those without much money can never borrow money from those who have it, and sometimes they need to borrow that money even at a reasonable interest rate, eg to buy a house.
Lenders realistically need to make some level of interest in order to at least cover the inevitable losses from non payment of some proportion of the loans made, otherwise they'd soon see their money disappearing if they were lending it out at no interest rate.
I'd definitely support a limit on interest rates, and charges made for borrowing money though - nuts to charge £30 for going into an overdraft by a few quid, and similar stuff that can actually make the pay day lenders rates seem almost sensible in comparison for a very short term loan.