مَا زَالَ الْمَرِيضُ صَابِرًا
Translation: The patient has continued to be patient.
مَا: negative particle.
زَالَ: past incomplete verb.
الْمَرِيضُ: nominative ism zāla.
صَابِرًا: accusative khabar zāla.
Here mā zāla combines into a continuative sense. Dropping mā alters this recognized use and its meaning.