Quatrain 32

  Oh, threats of Hell and Hopes of Paradise!
One thing at least is certain--
This Life Flies;
One thing is certain and the rest is Lies;
The flower that once has blown for ever dies.

FitzGerald, Stanza LXIII, 4th ed.
(FG has italicized "This" in line 2)

See Quatrain 12 on our site.  Presented there (and here, below) is the quatrain-source for this stanza, Bodleian-Ouseley 35.  Also in Dashti 17, Saidi 88, Hedaayat 47, Whinfield 107.  Note that our Quatrain 32 is almost a repetition of 12.

The stanza for FitzGerald's first edition, revised in the second edition of 1868 (as Stanza LXVI) and occurring as Stanza LXIII from thereon:

Oh, come with old Khayyam and leave the Wise
To talk: one thing is certain, that Life flies.
One thing is certain and the rest is Lies;
The flower that once has blown for ever dies.

FitzGerald, Stanza XXVI, 1st ed.

Here is the source (O 35 and also in the Calcutta according to Heron-Allen, 97 and Arberry, Romance ... 208):

می خور که به زیر گِل بسی خواهی خفت
بی مونس و بی حریف و بی همدم و جفت
زنهار به کس مگو تو این زار نهفت
هر لاله که پژمرد نخواهد بشکفت

Dashti, quatrain 17, p. 247

mey khor ke be zir-e gel basi khaahi khoft
bi munes o bi harif o bi hamdam o joft
zenhaar be kas magu to in raaz-e nehoft
har laale ke pazhmord nakhaahad beshkoft

Drink wine! long must you sleep within the tomb,
Without a friend, or wife to cheer your gloom;
Hear what I say, and tell it not again,
"Never again can withered tulips bloom."

Whinfield, quatrain 107

Ah, drink! Beneath the earth you shall be lain,
Without friend, mate or spouse you shall remain—
This hidden mystery to none explain:
The tulip withered won't its bloom regain!

Saidi, quatrain 88

According to Heron-Allen, the Ouseley MS 35, which reads exactly the same as our Dashti quatrain, provided two source-quatrains used by FitzGerald.  The last two lines of the Ouseley 35 (= Dashti's last two lines) inspired Stanza LXIII above (Heron-Allen, 97).

The Ouseley 35 (= Dashti's first two lines) inspired Stanza XXIV, 4th ed. (Heron-Allen, 41) below:

Ah, make the most of what we yet may spend,
Before we too into the Dust descend;
Dust into Dust, and under Dust, to lie,
Sans Wine, sans Song, sans Singer, and—sans End!

FitzGerald, Stanza XXIV, 4th ed

What was FG's inspiration for the first two lines of Stanza XXVI (first edition) and the revised second and subsequent editions?  Arberry, 208: "FitzGerald supplied the greater part of this stanza out of the general context of Omar's poems." I like to believe that FitzGerald's muse must have appeared to him during his walks where he worked out his ideas and his versification.