Is it permissible to agree to purchase a house in installments over two years, provided that the seller stipulates that the house may not be sold until the installments are paid?

The seller is permitted to stipulate to the buyer that the sold item not be resold until its full price has been paid. This is the view held by the Malikis, who considered it akin to a pledge (rahn). Likewise, the seller is permitted to stipipulate that the sold item be pledged with him as security for his right to collect the deferred installments. Therefore, there is no objection to the aforementioned transaction and the pledging of the house with the seller until the price is fully collected.