Breakdown of Il a obéi, récompense-le !
il
he
avoir
to have
le
him, it (masculine direct object pronoun)
obéir
to obey
Questions & Answers about Il a obéi, récompense-le !
Why does le come after the verb in récompense-le?
Why isn't there an "s" at the end of récompense? Isn't the tu form récompenses?
You are right that the normal present tense form is tu récompenses. However, for verbs ending in -er, you must drop the final s in the tu form of the imperative (the command form). Therefore, it becomes récompense-le !
How do we know le means "him" and not "it" here?
How is the past tense formed in Il a obéi?
This is the passé composé. It uses the helping verb a (from avoir) and the past participle obéi. Because the infinitive is obéir (to obey), you form its past participle by simply dropping the final r, which is the standard rule for regular -ir verbs.