من لا يحضره الفقيه, volume 3, page 281

Hadith.4014 - Sama'ah asked him about food, dates, and raisins. Imam (as) said: "It is not permissible to exchange two for one of any of these, except if you change it from one type to another. When you change it, then there is no harm in exchanging two for one or even more than that."

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.

Hadith.4015 - It is narrated from Muhammad ibn Qays, who said: I heard Abu Ja'far Imam Muhammad ibn Ali Al-Baqir (as) say: "It is disliked to exchange one wasq of dates from Medina for two wasqs of dates from Khaybar, because the dates of Medina are of better quality." Imam (as) also said: "It is disliked to sell dates in exchange for fresh dates, even if measured equally, with a delayed payment, because fresh dates dry out and decrease in volume."

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.

Hadith.4016 - Ali ibn Ja'far asked his brother Imam Musa ibn Jafar Al-Kadhim (as) about a man who gave his servant ten dirhams on the condition that the servant would pay back ten dirhams each month. Imam (as) said: "There is no harm in that."

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.

Hadith.4017 - Dawud ibn al-Husayn asked Abu Abdullah (as) about exchanging one sheep for two sheep and one egg for two eggs. Imam (as) said: "There is no harm, as long as it is not something measured or weighed."

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.