Why is 'kyrie' separated into three disinct musical phrases?

The 'kyrie' is often separated into three distinct musical phrases to emphasize its liturgical significance and to enhance its emotional impact. Each phrase typically corresponds to a different plea for mercy, allowing for a more expressive and reflective interpretation. This structure also facilitates a call-and-response dynamic within a choral setting, creating a more engaging and participatory experience for both singers and listeners. The division into phrases helps to highlight the text's meaning while allowing for varied musical exploration.