Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and then turn and tear you to pieces.
- Matthew 7:6
This verse in particular reminded me of a story about a teacher who, having been completely ignored for an entire lesson, cried out upon hearing the bell, "Wait, I have one more pearl to cast...."
Some few of the students recognised the allusion, and were suitably chastened. I wonder how many of today's students, secondary or tertiary, would understand what was being said to them?