It is not permissible to deal in riba (usury, interest) or to help with that in any way, shape or form, because Allaah says (interpretation of the meaning):
“Help you one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression. And fear Allaah. Verily, Allaah is Severe in punishment”
It was narrated that Jaabir ibn ‘Abd-Allaah (may Allaah be pleased with him)said: The Messenger of Allaah (peace and blessings of Allaah be upon him) cursed the one who consumes riba and the one who pays it, the one who writes it down and the two who witness it, and he said: they are all the same.
As for the cheque which constitutes a loan with interest, it is not permissible to write it or help with it. The one who does that is exposing himself to the curse and being cast out from the mercy of Allaah.
The scholars of the Standing Committee for Issuing Fatwas were asked: What is meant by the one who writes down riba, as mentioned in the hadeeth of Jaabir that was narrated by Muslim, where he said: the Messenger of Allaah (peace and blessings of Allaah be upon him) cursed the one who consumes riba and the one who pays it, the one who writes it down and the two who witness it, and he said: they are all the same? Is the one who writes down riba the one who just writes that document? Or could it include any individual who has nothing to do with the riba institution, but because of his work as an accountant, he adds and subtracts numbers in documents that have nothing to do with the original document of riba? Is that accountant regarded as writing down riba, or does this wording apply only to the one who writes that document and does that not apply to anyone else and does the curse not apply to anyone else?
The hadeeth about the one who writes down riba being cursed is general in meaning, and it includes the one who writes the original document, the one who copies it if the original wears out, and the one who records the amount in records of accounts, and the accountant who works out the rate of interest and adds it to the original sum, or send it to the depositor, and so on. And Allaah is the source of strength. May Allaah send blessing and peace upon our Prophet Muhammad and his family and companions.
End quote from Fataawa al-Lajnah al-Daa’imah.
So beware of taking part in this grave sin.
And Allaah knows best.