فَلْيَضْحَكُوا قَلِيلًا وَلْيَبْكُوا كَثِيرًا
Let them laugh little and weep much. (At-Tawbah 9:82)
Both clauses use lam al-amr to express a directive: falyadhaku and walyabku. Laughing and weeping are contrasted, as are little and much. These parallel requests contribute to one overall rhetorical purpose.
Grammar: In falyadhaku, the present verb is jussive, marked by deletion of nūn; the plural wāw is its subject pronoun. In walyabku the conjunction links a second directive with the same pattern.