Suppose the information is that a teacher is absent today. The following are additional teaching illustrations of the source rule.
1. Uncommitted: «الْمُدَرِّسُ لَيْسَ حَاضِرًا» — the teacher is absent; a plain report suffices.
2. Hesitant: «مَا الْمُدَرِّسُ بِحَاضِرٍ» — the negation is strengthened.
3. Strong denier: «وَاللَّهِ مَا الْمُدَرِّسُ بِحَاضِرٍ» — an oath adds further reinforcement.
This does not recommend taking oaths routinely. It illustrates levels of expression. In real speech, emphatic devices should be used only when warranted by the situation.