Who said this the spoken words are your master and the unspoken words are your slave?

The suggestion that it is a Chinese proverb, may be true, as it reflects a universal and eternal truth. Though I could only trace it to Solomon Ibn Gabirol ben Judah, a Spanish Jewish leader, poet and philosopher, who lived from 1021-1058. It is also known as an Irish proverb, and was quoted by Abraham Lincoln.