requirement of successor's justice in contractual will from the viewpoint of imamiah jurisprudents

imamiah jurisprudents have disagreed about the requirement of successor's justice in contractual will from past to now. some of them have considered it as the condition of accuracy of will, and others consider it ineffective in accuracy and inaccuracy of will. considering that this issue has much scientific and practical results and that if we accept any of these two views, our understanding of the successor and his essential conditions will be different, it seems necessary that the opinions and reasons raised by agreeable and disagreeable jurisprudents are examined and the origin of differences is extracted among their writings, and after comparing their reasons and basics, the more accurate theory is chosen, and thereby a comprehensive, accurate and exact view about the requirement of successor's justice is accepted.