All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The jurists conditioned the acceptance of the testimony of the person who sighted the moon (crescent) of Ramadan that he possesses the characteristic of 'Adl (i.e. piety and trustworthiness in the matters of religion). However, they differed about what is exactly meant by 'Adl. The jurists defined it as follows: "One who avoids grave major sins and does not persist in committing small sins"; as mentioned in the Fiqh Encyclopaedia.
The Fiqh Encyclopaedia reads: "The Hanafi and Shaafi'ee Schools of jurisprudence are of the view that the characteristic of 'Adl in sighting the moon of Ramadan should be an apparent characteristic. For them, the sighting of the moon by a slave or a woman is accepted. Whereas, the Maaliki and Hanbali Schools of jurisprudence are of the view that what is meant by 'Adl is the inward characteristic, so a testimony of a person whose characteristic of 'Adl is not apparent, is not accepted as he is not trusted, in the same way the testimony of a dissolute person is not accepted."
There is no doubt that a person who wears amulets other than the Quran and those who seek help from other than Allaah lack the characteristic of 'Adl; the least that could be said about them is that they are innovators, so they lack the quality of 'Adl inwardly and outwardly.
This is in general, however, if one is informed by a specific person that he sighted the moon and he knows him enough to trust his statement, then it is an obligation for the informed person to accept his testimony and fast accordingly even if the person who informs him is dissolute.
The Fiqh Encyclopaedia further reads: "The jurists are of the view that if a person is informed by an informer whom he trusts his sighting of the moon of Ramadan, then the informed person is obliged to fast even if the informer is a dissolute person."
Finally, it should be noted that 'Adl Muslim people should seek to see the moon by themselves if they know that those who are appointed to see the moon lack the quality of 'Adl and they accept the testimony of the non-'Adl people.
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Allaah Knows best.