Some of the ‘Ulamaa considered Al-Butlaan and Al-Fasaad as two terms with the same meaning however the reality is that the Fasaad differs from the Butlaan. That is because the Butlaan represents the non-agreement to the command of the Shaari’ in respect to the Asl (origin) of the matter i.e. its Asl (origin) is forbidden by the Shar’a. That is like Al-Khamr or the sale of Malaaqeeh which is what is found in the bellies of living creatures related to impregnation. This therefore represents the non-agreement or non-conformity with the command of the Shaari’ in terms of the absence of a Rukn from the Arkaan of the contract or the absence of a Shart from the Shuroot violating the origin (Asl) of the action or contract, like the condition of Wudoo’ in respect to the Salaah.
As for the Fasaad, then in respect to the Asl (origin) it is in agreement with the command of the Shaari’ however it includes a Wasf (description) that is not from the Asl of the action or the contract that is contrary to the command of the Legislator. This would be like the marriage contract in which the Mahr (dowry) has not been specified as this would make it Faasid but not Baatil. The Fasaad (corruption) would then be removed through the specification of the Mahr. The Fasaad in respect to the contract represents a deficiency that is possible to complete so that the contract can become Saheeh whilst the Butlaan in respect to the contract necessitates a new contract that meets the required and necessary pillars and conditions. Al-Fasaad in respect to the ‘Ibaadaat are not conceivable as the ‘Ibaadaat are either Saheeh or Baatil (valid or invalid). That is because the one who follows their conditions and pillars finds that they are all connected and related to the Asl (origin) (of the action). As such, the Tahaarah (being in a purified state) is a Shart for the Salaah and if this is not fulfilled then the action would be void and invalid (Baatil). Similarly, the Sujood (prostration) is a Rukn of the Salaah and if it does not take place then the Salaah would be Baatil.
As for the Mu’aamalaat (transactions) then Al-Butlaan and Al-Fasaad are both conceivable. Therefore, if a fundamental (Asaasiy) condition of a contract that violates the Asl (origin) of the contract was missing then the contract would be Baatil (void and invalid). If the condition however was not violating the Asl of the contract, the contract would then be Faasid (corrupted).
The Hanafiyah said: The Aqd (contract) that is not Saheeh is divided into two categories: The Baatil and the Fasaad. If the deficiency or violation occurred in the pillar of the contract it would be Baatil and no effects will be built upon this invalid transaction as a consequence of it, like the sale of carrion (Al-Maitah) for example. That is because the ownership of the carrion does not result from it nor does the ownership of its price or value and there is no permissibility in respect to benefitting through the Maitah (carrion) or its price.
If, however, the flaw, violation or deficiency (Khalal) occurred in one of the conditions of the contract then the ‘Aqd would be Faasid and some effects would be consequential to it like the contraction of the marriage without the specification of the Mahr. That is because the consequences of the Saheeh (valid) marriage are built upon it whilst the Fasaad (corruption or corrupted element) is removed by specifying the Mahr.