Yung-chia also emphasized the importance of making vows. Without sincere vows, a practitioner will progress slowly and accomplish little. Buddhas and Bodhisattvas attained their positions because they all made such great vows as the Four Bodhisattva Vows.

Now, let us turn to the work itself. The Song of Enlightenment was written in the beginning of the eighth century. However, the first commentary did not appear until the eleventh century, during the Sung dynasty (906-1278). There are four Chinese commentaries on the Song of Enlightenment, the last of which was written in the fourteenth century. There are two important Japanese commentaries, written in the eighteenth and nineteenth centuries, and in the English language there is a commentary by Charles Luk.

The dating and authorship of the Song of Enlightenment are in question. In comparing the Song of Enlightenment with Yung-chia's other works, scholars have found inconsistencies which suggest that the song was written by someone else. For instance, the Song of Enlightenment is not included in the Ch'an-tsung Yung-chia Chi along with his ten other works. Furthermore, in the official history of the T'ang dynasty, Yung-chia and his works are mentioned in the chapter on "Arts, Religion and Literature, " but the Song of Enlightenment is omitted.

The song itself contains inconsistencies and contradictions. Two lines in the Song of Enlightenment refer to the first six Ch'an Patriarchs symbolically transmitting the Dharma with the robe from one generation to the next. However, this ritual did not become popular until sometime after Yung-chia's death.