Is it permissible for a partner to lease his share of merchandise in a shop to his co-partner for a year, with the ensuing profit or loss, and then return as a partner with his previous share, by mutual agreement between them?

This contract is void because it stipulates a fixed amount of money, which invalidates the partnership. It is not permissible for one of the partners to be given a fixed amount of money, or to profit from a specific, known sum. Rather, the share of each partner must be an undivided share of the profit. Furthermore, the condition of guaranteeing the capital in case of damage is considered a void condition.