«أَمَّا بَعْدُ»
Now, to what follows.
The formula “ammā baʿd” marks the move from preliminary praise to the substantive message. Instead of an elaborately constructed metaphorical bridge, a recognized discourse signal indicates the new section.
The source connects the discussion with faṣl al-khiṭāb. The practical rhetorical effect is clear: the listener understands that the opening formalities are over and the main address is beginning.