Learn Spanish (Latin America): La orden del médico fue clara.

Orden is a word that changes meaning depending on its gender. El orden refers to arrangement or sequence, like alphabetical order or a tidy room. La orden means a command or directive. Since the doctor is giving a command, we use the feminine form here.

Why use fue instead of estuvo to say the order was clear?

We use fue, the preterite of ser, because being clear was an essential characteristic of the command itself. When describing the defining qualities of a past statement, idea, or event, we use ser rather than estar.

How does this sentence relate to reporting past commands with the imperfect subjunctive?

This sentence sets up a past-tense command using fue. If we wanted to state what the doctor actually commanded, we would use que followed by the imperfect subjunctive. For example, to say that the doctor ordered you to rest, you could extend the sentence like this: La orden del médico fue clara: que descansara.