Necessary Conditions for& Possibility of Performing the Lien Right in the Contractual Omission Obligations(Comparative Study Between Afghanistan& Iran Civil Law)

Lien right is one of sanctions which is determined for protection from warrantee where contract is faced with delay. But possibility of performance of this right has not been studied in contractual omission obligations. Whereas the lien right means suspension of performance of obligation and the contractual omission obligation means non-performance of a specified act, this question has not been asked till now, if there are necessary conditions for it, is it possible to perform this right in practice. Also for differences between Afghanistan& Iran law, necessary conditions for performing the lien right has been studied in both system. Information for this paper has been gathered by referring to library sources and studied by analytical-descriptive methods. According to the results, instances for performance and waive of the lien are more in Afghanistan law than Iran. Additionally, by studying legal general principles, Islamic jurisprudence rules and the cases studies ofimplementation of this right, a general principle was created for using the lien right in the contractual omission obligations, this is, if implement of this right eventuated in loss of matter of obligation, fulfilment of lien right is not possible, and where this does not take place, warrantee has the authority to do it.