the legal status of condition to guarantee profit

one of important conditions of capital, is the condition to guarantee profit. with due attention of illegality of the free- interest and forbidding of the usury under the islamic and iranian law, it is necessary that; the legal status of this condition and it’s legal sanction to be considered it seems that, the condition to guarantee profit is a condition about the performance of act by witch the guarantor promise to obtain the profit that they predetermined by mutual consent. the jurists of islamic schools, although, believed that; pre-specification of investment profits in any form of partnership is not allowed but there is not any proof to nullify such condition since just as profit may be shared between two parties, the profit of one party may be pre-specified and it dose not contradict any canonical text in the qur’an and sunnah. consequently the condition, according to principle of conditions, is valid