forgiveness of sin (deror) in the old testament meant a debt cancellation (jubilee), this was abolished by the pharisees, jesus tried to return debt cancellation and was persecuted for it.if you look at the early history of islam, zakat was quite literally an introduction of the debt jubilee into a usurious society filled with debt slavery that had accumulated too much debt to fully function, this is why the theme of forgiveness is so prominent.now how exactly did zakat function in the earliest generations of islam? everyone nowadays believes zakat is some form of personal charity you give to some random bum or your mosque and thats it.in reality, it was originally collected (this is why zakat is annual) and distributed to free muslims from debt slavery, with duty being eventually being completed when every indebted muslim had reached the nisab (something like a starting capital) of 85-90 grams of gold (10.000 usd today), giving the community financial autonomy and financial freedom to fight for its cause.this is actually a lot more extreme than the biblical debt jubilee, which was every 7 years or so, and only erased the debt, meaning you were simply left with no money to spend.when you realize this shift in perception, its clear why muslims nowadays are so unsuccessful compared to their pious predecessors.
