Final answer:
The song 'Thy Hand, Belinda' is from the opera 'Dido and Aeneas' by Henry Purcell. It is sung by the character Belinda, who expresses concern for Dido's sadness and offers her comfort. The song highlights the emotional support and friendship between the two characters.
Step-by-step explanation:
The song "Thy Hand, Belinda" is from the opera "Dido and Aeneas" by Henry Purcell. It is sung by the character Belinda, who is a close friend of the protagonist, Dido. In the song, Belinda expresses concern for Dido's sadness and asks her to be comforted by her hand. The song is about the emotional support and encouragement between friends.