Idiom【自相矛盾 zì xiāng máo dùn 】

Idiom【自相矛盾 zì xiāng máo dùn 】
Spear：Weapon for piercing the enemy.  Shield: Shield for protecting oneself.

The story for this idiom is as follows:

There was a seller for spear and shield at the ancient times. He said that his spear was the sharpest one and no spear can pierce it. He also said that his shield was the hardest one, no spear can pierce it. "What will happen if you prick your shield with your spear", someone asked. The seller was speechless.

This idiom means that someone says or does something impenetrable. (Wed Editor: Zhang Xiaomei) [Shun Net English Version]