Praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
The contract of Murabaha to the purchase orderer consists of three phases: A promise to purchase, purchasing the commodity from the supplier (Seller) and selling the commodity to the customer (Buyer).
During the first phase, it is allowed for the bank to make the customer sign a document of commitment to buy the commodity in the event the bank bought it from the supplier. This aims to ascertain the customer`s seriousness about purchasing the commodity.
Moreover, it is also permissible for the bank, during the first phase, to ask the customer to bring a guarantor or a mortgage. For more details, kindly check the Shafie book "Moghni Al-Mohtaj Ela M`arifat Alfaz Al-Minhaj, V.3:202."
In addition, it isn`t allowed that the third phase precedes the second phase. In other words, it isn`t allowed for the bank to sell the Murabaha commodity to the customer before buying it from the supplier and taking possession of it. Ibn Abbas (Allah be pleased with them) reported Allah's Messenger (PBUH) as saying: "He who buys food-rain should not sell it until he has taken possession of it. Ibn Abbas (Allah be pleased with them) said: I regard everything like food (so far as this principle is concerned)." {Bukhari & Muslim}.
Some employees of the Islamic banks may make the client sign the promise to purchase, the guarantees and the contract before the bank purchases the commodity from the supplier while the bank delays signing and approving the contract until it purchases the commodity from the supplier and takes possession of it. This is to spare the client the time and the technicalities. However, this act entails violations of the rules of Sharia because acceptance precedes offer and the general rule is that offer and acceptance should be conducted between contracting parties in the same sitting. Therefore, it isn`t valid that acceptance precedes offer.
In conclusion, it is allowed for the bank to take guarantees from the customer before it takes possession of the commodity; however, it isn`t allowed for the bank to make the customer sign the contract of Murabaha before it (bank) takes possession of the commodity. And Allah the Almighty knows best.