Quatrain 6

چون ابر به نوروز رخ لاله بششت
بر خیز و به جام باده کن عزم درست
کاین سبزه که امروز تماشاگهٔ توست
فردا همه از خاک تو بر خواهد رست

Dashti 62, p. 255  (& see weblog Quatrain 13)

chon abr be nowruz rokh-e laale beshost
bar khiz o be jaam-e baade kon  azm dorost
kin sabze ke emruz tamaashaagah-e tost
fardaa hame az khaak-e to bar khaahad rost 

While cloudbursts at Nowruz wash the tulip’s face
rise and fetch the cups it’s time for drinking
this patch is yours but only for today

tomorrow a meadow sprouts from your dust

and this companion piece:

ابر آمد و زار بر سر سبزه گریست
بی بادهٔ گلرنگ نمی‌شاید زیست
این سبزه که امروز تماشاگهٔ ماست
تا* سبزه خاک ما تماشاگهٔ کیست

Hedaayat, quatrain 61, Forughi 8 (not in Dashti)

abr aamad o zaar bar sar-e sabze gerist
bi baade-ye golrang nemishaayad zist
in sabze ke emruz tamaashaagah-e maast
taa sabze-ye khaak-e maa tamaashaagah-e kist

A cloudburst came poured tears on the green
what is life without a cup of wine ...

this green is ours to enjoy today
who follows us in the meadow of our dust

* تا in the last line is an interjection -- it draws attention to what follows:
"well now, who's to come after us" 

Translation & Discussion of the Dashti quatrain: 1. When the raincloud at NewYear has washed the face of the tulip - Nowruz, which comes at the vernal equinox when the country gives way to re-emerging life and greenery:  From Hafez, ghazal 160, Khanlari; 164, Qazvini

نفس باد صبا  مشک‌فشان خواهد شد  
عالم پیر دگر باره جوان خواهد شد 
ارغوان جام عقیقی به سمن خواهد داد 
چشم نرگس به شقایق نگران خواهد شد


The breath of the east wind
scatters its musky fragrance
the old world once more grows young
 Judas trees give their scarlet cups to jasmines
narcissus-eyes will gaze at anemones ...    

2. Rise and be fully intent on (drinking) a cup of wine -- "fully fix your resolve on drinking a cup of wine."   From what follows the time for enjoyment is now.  3. Since this green meadow, which is our viewing/showplace today. 4. Tomorrow, all of it will spring forth from our dust.  FitzGerald did not use the first two lines of our Quatrain 6 or the companion piece in his Stanza XXIII below, but Heron-Allen notes that he employs the last two lines of both, a familiar refrain, "the echo of a sentiment that recurs continually in the originals":

And we, that now make merry in the Room
They left, and Summer dresses in new bloom,
Ourselves must we beneath the Couch of Earth
—ourselves to make a Couch—for whom?
Stanza XXIII, 4th ed.

"They" in line 2 are likely the یاران موافق , yaaraan-e movaafeq, "friends of one mind" 
For some we loved, the loveliest and the best ...Have drunk their Cup a Round or two before/And one by one crept silently to rest (Stanza XXII, 4th ed.).