Answer:
"Light, joy, and leisure".
Explanation:
George Herbert's poem "Heaven" is a metaphysical poem where he talks about or rather, asks questions regarding heaven. The poem is more of a question about what lasts longer than mortal life elements.
The short poem posed in the form of a question-answer system where "echo" replies to his questions. And the things that Echo says will last are "Light, joy, and leisure", as Echo replies "ever" to the question "Light, joy, and leisure; but shall they persever?"
