I've been thinking of John all day, and this poem, by Maya Angelou, seems appropriate:

When Great Trees Fall

by Maya Angelou

When great trees fall,

rocks on distant hills shudder,

lions hunker down

in tall grasses,

and even elephants

lumber after safety.

When great trees fall

in forests,

small things recoil into silence,

their senses

eroded beyond fear.

When great souls die,

the air around us becomes

light, rare, sterile.

We breathe, briefly.

Our eyes, briefly,

see with

a hurtful clarity.

Our memory, suddenly sharpened,

examines,

gnaws on kind words

unsaid,

promised walks

never taken.

Great souls die and

our reality, bound to

them, takes leave of us.

Our souls,

dependent upon their

nurture,

now shrink, wizened.

Our minds, formed

and informed by their

radiance, fall away.

We are not so much maddened

as reduced to the unutterable ignorance of

dark, cold

caves.

And when great souls die,

after a period peace blooms,

slowly and always

irregularly. Spaces fill

with a kind of

soothing electric vibration.

Our senses, restored, never

to be the same, whisper to us.

They existed. They existed.

We can be. Be and be

better. For they existed.