What is the ruling if the assignment is made by someone who has no debt against the assigned party, or to someone who has no debt against him?

Primary text

If one who has no debt assigns to a man who owes him a debt, this is not an assignment but a mandate, taking the ruling of mandate. This is because assignment involves the transfer and transformation of a right, which is absent here. If one who owes a debt assigns to one who owes him nothing, it is not an assignment according to Ahmad; the assigned party is not obliged to pay, nor the assignee to accept, as assignment is an exchange. If the assignee takes possession, he reverts to the assignor as a loan. If the assignee remits the debt without possession, the remission is invalid. If the assignee takes possession and then gifts it, the assigned party reverts to the assignor for having made payment, which necessitates a new contract; alternatively, he might not revert since he paid nothing himself. If one who owes nothing makes an assignment, it is a mandate to borrow, not an assignment, because assignment requires a debt against a debt, and neither exists here.