Besides the Lord speaking in Doctrine and Covenants Section 25, the only other people who use the words, "My soul delighteth" are Isaiah and Nephi. The only two who use the words "the robes of righteousness" are Isaiah and Nephi. Jacob uses this phrase, but he is quoting Isaiah. Nephi loves Isaiah and his writings, and he is so familiar with these words and passages that he may not even have realized that he was quoting any phrase in particular.