Among the arguments of the Murji'ah is the [hadith of the] slave girl to whom the Prophet, may Allah bless him and grant him peace, said: "Free her, for she is a believer." The proof against them in this [matter] is that the Prophet, may Allah bless him and grant him peace, had asked her about some of the ordinances of faith.
وَمِنْ حُجَّةِ الْمُرْجِئَةِ بِالْجَارِيَةِ الَّتِي قَالَ النَّبِيُّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: «أَعْتِقْهَا؛ فَإِنَّهَا مُؤْمِنَةٌ» وَالْحُجَّةُ عَلَيْهِمْ فِي ذَلِكَ؛ لِأَنَّ النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَدْ سَأَلَهَا عَنْ بَعْضِ شَرَائِعِ الْإِيمَانِ
