The ordinary third- and first-person imperative is formed with lām al-amr «لِـ» before an imperfect. The verb becomes jussive: a regular singular usually ends in sukūn, while an inflectional nūn is removed where applicable.
Word / formMeaning / explanation
يَفْعَلُ ← لِيَفْعَلْlet him do.
يَفْعَلَانِ ← لِيَفْعَلَاlet the two men do.
يَفْعَلُونَ ← لِيَفْعَلُواlet the men do.
أَفْعَلُ ← لِأَفْعَلْlet me do.
The verbal root stays constant; the prefix and inflectional ending change to express the command.