tree lives for itself.

Shall, then, this human heart live for itself; gather and store up for
its own delectation, for its own good?

There is no such thing as one's own good:

Goodness is mutual, is communal; is only guided by giving and receiving.
Wherefore

O frail, weak, human heart, seek thou out carefully constructed means by
which to transmute sunshine and soil and showers into flowers and fruit.

***