Isa bin Hammad bin Muslim, Zaghba عيسى بن حماد بن مسلم أبو موسى زغبة · The Book of Zakah

"The Messenger of Allah said: 'There is no man who has wealth and does not pay the dues of his wealth, but a baldheaded Shuja'a will be made to encircle his neck, and he will run away from the Book of Allah: 'And let not those who covetously withhold of that which Allah has bestowed on them of His Bounty (wealth)' think that it is good for them (and so they do not pay the obligatory Zakah). Nay, it will…

"We used to pay Salaqatul Fitr when the Messenger of Allah was among us; a Sa' of food, or a Sa' of dates, or a Sa' of barley, or a Sa' of cottage cheese. We continued to do so until Mu'awiyah came from Ash-Sham and one of the things that he taught the people was when he said: I think that two Mudds of wheat from Ash-Sham are equivalent to a Sa' of this, So the people took to that."