Where did Aquinas find this gloss?

The following passage occurs in Aquinas's *Summa Theologica* ([Supp 91.3](https://www.ccel.org/ccel/aquinas/summa.XP_Q91_A3.html)) : > A gloss on Isaiah 30:26, "The light of the moon shall be as the light > of the sun," says: "**All things made for man's sake deteriorated at his > fall, and sun and moon diminished in light**." This diminishment is ... What exactly or who exactly is Aquinas quoting from here (the **bold** text)? Does this work still exist? And is there a general way to find out where these "glosses" are coming from?