What is the ruling on agreeing with a friend to share the capital of sold goods and divide the profit with him in exchange for his help in selling, while guaranteeing that he will not incur a loss?

It is permissible for two to enter into a partnership where one contributes with his capital and labor, and the other with his labor. This is considered a valid Mudarabah (profit-sharing partnership) according to the Hanbalis. The profit in such a partnership is distributed according to the agreement, while the loss is borne by the owner of the capital.