What is the key difference between «ضَرَبَ الزَّيْدُونَ» and «الزَّيْدُونَ ضَرَبُوا»?

Rules of the Fāʿil: Explicit Nouns, Pronouns, Number and Gender

• The first has an explicit subject; the second has a subject pronoun
• Both have an object
• The first is passive
• Neither has a verb