Here are the last two musical phrases:
The second verse ends with the lines "To tend Thy flock, and thus to prove / How dearly they [pastors] the Shepherd love." "Dearly" is sung with a melisma (C B A), musically giving a sense of degree (for "how").
The fourth verse ends with the lines "With all the bright celestial host [singing], / To Father, Son, and Holy Ghost." Here, "host" is sung with a melisma (C B), giving something of a sense of the entirety of "all."