Exchanging Labor by Sale in Imami Jurisprudence

Labor is exchanged in different contracts in Imami jurisprudence. One of these contracts that exchanging labor is possible by it is sale contract. Possible of exchanging labor by sale contract in Imami jurisprudence is problem of this paper.
Purpose of this paper is gathering proofs of permit of exchanging labor in Imami jurisprudence and juridical explaining verdict of exchanging labor by sale contract
The explanation of the contracts that in Imamieh jurisprudence, in the form of which human benefit, that is, work, can be acquired by another, is very important in the economic and legal systems based on the Imams' jurisprudence; one of its most important effects is the determination of the nature and amount of the work of the worker. Domain of this article is researching likely reasons of selling labor and also researching views of Imami jurists about exchanging labor by sale contract.
In the last, after explaining likely reasons of selling labor and analyzing their implications, and gathering and reflection on views of Imami jurists, it was resulted that exchanging labor by sale is not permitted in Imami jurisprudence