All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
The effort exerted in writing a research paper can be divided into two parts:
1- Form-oriented: typing, formatting, indexing, and collecting bibliographies. There is no harm in helping students accomplish these tasks whether for a fee or not.
2- Content-oriented: paraphrasing, deriving conclusions, ordering ideas, and clarifying controversial issues. Here, it is prohibited to help students accomplish the afore tasks because it involves leading their teachers to believe that that it is their own effort; whereas, a research paper is a means of assessment that aims to make the student look for information from certified sources, and become accustomed to paraphrasing and ordering ideas to arrive at conclusions.
As a result, this student gets a grade that he doesn`t actually deserve, and it equates him, before the teacher, with the student who worked hard and excelled in writing his own paper. In this regard, Prophet Mohammad said: "The one who makes a false statement of that which one has not been given is like one who wears a garment of falsehood." {Agreed upon}.
In addition, the student that submits such a research paper as if it was his own effort makes him a liar, and lying is one of the grave sins since Allah, The Almighty, Says: "O ye who believe! Fear God and be with those who are true (in word and deed)." {At-Tawbah/119}. And Allah Knows Best.
