Is it permissible for a brother to withdraw from a partnership and cease working on a website after agreeing to complete it, or is he obligated to fulfill his promise, knowing that his withdrawal would cause harm to his partner?

Most scholars are of the opinion that a partnership contract is not binding, and any of the partners may withdraw from it, unless it is for a specified period and withdrawal before that period would cause harm, or if the mudarib (managing partner) has commenced work. The Malikis disagreed, holding that a partnership contract becomes binding simply upon its conclusion (by word or action).

If it is agreed to work until the completion of a specific project, then this is akin to a fixed duration. Therefore, the contract may not be dissolved before the completion of the work, especially if the work has begun and dissolution would result in harm. Contracts must be fulfilled, based on the Almighty's saying: ﴿O YOU WHO HAVE BELIEVED, FULFILL [YOUR] CONTRACTS﴾ (Quran 5:1) and the Prophet's (peace be upon him) saying: "Muslims are bound by their stipulations."