Al-Kāfi
Hadith 2442- عَلِيُّ بْنُ مُحَمَّدِ بْنِ بُنْدَارَ عَنْ أَحْمَدَ بْنِ أَبِي عَبْدِ اللهِ عَنْ أَبِيهِ عَنِ ابْنِ سِنَانٍ عَنْ أَبِي الْحَسَنِ (عَلَيْهِ السَّلام) قَالَ سَأَلْتُهُ عَنِ الإجَارَةِ فَقَالَ صَالِحٌ لا بَأْسَ بِهِ إِذَإ نَصَحَ قَدْرَ طَاقَتِهِ قَدْ آجَرَ مُوسَى (عَلَيْهِ السَّلام) نَفْسَهُ وَاشْتَرَطَ فَقَالَ إِنْ شِئْتُ ثَمَانِيَ وَإِنْ شِئْتُ عَشْراً فَأَنْزَلَ اللهُ عَزَّ وَجَلَّ فِيهِ أَنْ تَأْجُرَنِي ثَمانِيَ حِجَجٍ فَإِنْ أَتْمَمْتَ عَشْراً فَمِنْ عِنْدِكَ.
2. Ali ibn Muhammad ibn Bandar has narrated from Ahmad ibn abu ‘Abd Allah from his father from ibn Sinan who said: “I once asked abu al-Hassan (a.s.), about the case of a man who places himself for hire, and he said, 'It is permissible and there is no harm in it as long as he is sincere to the best of his ability. Musa (as) placed himself for hire and stipulated, saying, "If you wish, [I will work] for eight years, and if you wish, for ten." And Allah, the Exalted, revealed concerning this: 'That you serve me for eight years; but if you complete ten, that will be [a favor] from you.' (28:27)“