Muhammad said: Whoever reads "arba'a" (four) in the accusative case (nasb), the meaning is: It is incumbent upon them that one of them testifies four testimonies. It is also read in the nominative case (raf') as the predicate of the subject (khabar al-ibtida'); the meaning is: The testimony of one of them that repels the prescribed punishment for slander is four testimonies.
قَالَ مُحَمَّدٌ: مَنْ قَرَأَ (أَرْبَعَ) بِالنَّصْبِ، فَالْمَعْنَى: فَعَلَيْهِمْ أَنَّ يَشْهَدَ أَحَدُهْمَ أَرْبَعَ شَهَادَاتٍ وَهِيَ تُقْرَأُ بِالرَّفْعِ عَلَى خَبَرِ الِابْتِدَاءِ؛ الْمَعْنَى: فَشَهَادَةُ أَحَدِهِمُ الَّتِي تَدْرَأُ حَدَّ الْقَذْف أَربع شَهَادَات.