The past is negated by placing مَا before an affirmative past-tense verb. The verb's form and its person/number markers remain unchanged; negation comes from the particle mā.
Word / formMeaning / explanation
فَعَلَ → مَا فَعَلَhe did → he did not do.
فُعِلَ → مَا فُعِلَit was done → it was not done.
فَعَلْنَا → مَا فَعَلْنَاwe did → we did not do.
فُعِلْنَا → مَا فُعِلْنَاwe were acted upon → we were not acted upon.
The particle does not turn active into passive or change first person into third person. It changes only the sentence's polarity.