Those who disliked that, once a salam payment is made, it be switched to something else

Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: When you make a salam (advance sale) contract for a foodstuff, do not on any account take another food in its place. If you wish to take fodder in its place, then take fodder.

Tawus said that a man made a salam (advance sale) contract for something and then could not find it, so he asked Sayyiduna Ibn Abbas (may Allah be pleased with them both). He (may Allah be pleased with him) said: Take goods; take goats.

Ibrahim (may Allah have mercy on him) said: When you pay the price in a salam (advance sale) contract, there is no harm in your taking goods in place of your capital.

Sayyiduna Umar (may Allah be pleased with him) said: When you make a salam (advance sale) contract for something, do not sell it onward until you take possession of it, and do not apply it to anything else.

Sayyiduna Ibn Umar (may Allah be pleased with them both) said: There is no harm in making a salam (advance sale) contract. Do not apply it to anything else, and do not sell it until you take possession.

Al-Hasan (may Allah have mercy on him) said: When you make a salam (advance sale) contract for something, take only the thing for which you made the contract, and do not make a salam contract for something that you will later exchange for another thing.

Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: The Muslims made salam (advance sale) contracts. So now, whoever makes a salam contract for wheat may not take barley, and whoever makes a salam contract for barley may not take wheat, and its measure and term must be known.

Al-Hasan (may Allah have mercy on him) said: Do not dispose of your salam before taking possession.