Al-Kāfi
Hadith 7032- مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عُثْمَانَ بْنِ عِيسَى عَنْ سَمَاعَةَ قَالَ سَأَلْتُهُ عَنِ السَّلَمَ وَهُوَ السَّلَفُ فِي الْحَرِيرِ وَالْمَتَاعِ الَّذِي يُصْنَعُ فِي الْبَلَدِ الَّذِي أَنْتَ فِيهِ قَالَ نَعَمْ إِذَا كَانَ إِلَى أَجَلٍ مَعْلُومٍ.
2. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ‘Uthman ibn ‘Isa from Sama‘ah who has said the following: “I once asked him (the Imam) (a.s.), about advance payment to receive goods on a date in future which is payment in advance for silk or goods made in the location where you live. He (the Imam) said, ‘Yes, it is lawful if the time is known.’”