The text explicitly extends the same scheme to negative assertions:
AddresseeSource exampleRhetorical force
Uncommitted«مَا زَيْدٌ قَائِمًا» / «لَيْسَ زَيْدٌ قَائِمًا»Plain denial
Hesitant«مَا زَيْدٌ بِقَائِمٍ»Reinforcement through bāʾ
Denier«وَاللَّهِ مَا زَيْدٌ بِقَائِمٍ»Oath plus reinforced negation
For the hesitant, the additional bāʾ strengthens the negation. For the denier, an oath is added. These are not three unrelated contents; they express the same negative proposition with degrees of emphasis suitable for three audience conditions.