The qualities perfected by the Buddha are the paramitas: generosity, ethics, patience, effort, concentration, wisdom. We see these qualities in the Pali Suttas on right speech, and helpful here are two suttas in the Middle Length Discourses, MN58 and MN41. The Buddha is the embodiment of the perfections and so when he speaks of, for example, right speech, he is describing himself.
Then we look at speech and silence in the koan collections. The trifecta of koans in the Blue Cliff Record, Cases 70, 71, and 72, all revolve around the koan: “How can words be spoken when your mouth is sealed shut?” And, finally, we venture onto Case 3 of Record of Empty Hall – “The World-Honored One Finally Pays Attention.”
wannabepoet 