وَ رَوَى اَلْعَلاَءُ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ عَنْ أَبِي عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ: فِي قَوْلِ اَللَّهِ عَزَّ وَ جَلَّ: فَكٰاتِبُوهُمْ إِنْ عَلِمْتُمْ فِيهِمْ خَيْراً قَالَ "اَلْخَيْرُ أَنْ يَشْهَدَ أَنْ لاَ إِلَهَ إِلاَّ اَللَّهُ وَ أَنَّ مُحَمَّداً رَسُولُ اَللَّهِ وَ يَكُونَ بِيَدِهِ عَمَلٌ يَكْتَسِبُ بِهِ أَوْ يَكُونَ لَهُ حِرْفَةٌ".
Al-Ala' narrated from Muhammad ibn Muslim, from Abu Abdullah (a.s), regarding the saying of Allah (swt), the Mighty and Majestic: "Then write [a contract of emancipation] for them if you know any good in them" (Surah An-Nur 24:33). Imam (a.s) said: "The 'good' refers to bearing witness that there is no god but Allah (swt) and that Muhammad is the Messenger of Allah (swt), and that the slave possesses a skill by which he can earn a livelihood or has a trade."