Could you please clarify the rule of commanding something implying a prohibition of its opposite?

Scholars differed regarding the issue of whether commanding something is the very same as forbidding its opposite, holding three opinions:

1. The First Opinion: That commanding something is the very same as forbidding its opposite. This is the view of the majority of Mutakallimun (theologians), but it is based on their assertion of the existence of "inner speech" (Kalam Nafsi). 2. The Second Opinion: That commanding something is not the very same as forbidding its opposite, but rather entails it. This is the most apparent and soundest of the opinions, because two opposites cannot coexist. 3. The Third Opinion: That it is neither the same nor does it entail it. This is the view of the Mu'tazilah and those who agreed with them.

Upon this difference of opinion are built jurisprudential issues such as: the ruling on divorcing one's wife if she violates a command that was considered a prohibition of its opposite, and the ruling on the invalidation of prayer if it is accompanied by something forbidden.