Four abilities of unhindered understanding and expression: （1） fawuai 法无碍 No mistake in teaching; （2） yiWuai 义无碍， No lack in regard to understanding the internal meaning of the teaching; （3） ciwuai 辞无碍 'unhindered speech，' that is， the understanding of all languages; （4） yueshuowuai 乐说无碍 'unhindered ease in explanation' which is the free use of the above three in the effort of saving all sentient beings.