Is a forward contract (Salaf) valid if it is due immediately (Hāl)?

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The forward contract (Salaf) requires a known deferred term (Ajal Ma'lum) for its validity. Imam Ahmad (in the narration of Al-Marwadhi), Abu Hanifa, Malik, and Al-Awza'i hold that it is not valid unless a deferred term is stipulated. The evidence for this position is the Prophet's saying: "Whoever enters into a forward contract concerning something, let him stipulate it in a known measure, or a known weight, for a known term." This command necessitates obligation. Furthermore, stipulating these conditions, including the term, is meant to define the parameters of the Salaf and prevent it without them, similar to how the absence of known measure or weight invalidates it. Moreover, the Salaf was permitted as a concession for ease (Rifq), and ease is only achieved through deferment; thus, the absence of deferment nullifies the ease and invalidates the contract, akin to written documents.