If the second clause restates or substitutes for the first, the discussion may concern complete connection. If the first invites a question and the second answers it, the relevant category is istiʾnāf.
Both may omit wāw, but the rhetorical grounds for omission differ.
Opening interactive controls...
Explanatory Resumption (Istiʾnāf) and Types of Implied Question
If the second clause restates or substitutes for the first, the discussion may concern complete connection. If the first invites a question and the second answers it, the relevant category is istiʾnāf.
Both may omit wāw, but the rhetorical grounds for omission differ.