Then to the Lip of this poor earthen Urn
I lean’d, the Secret of my Life to learn:
And Lip to Lip it murmur’d — “While you live,
“Drink! — for, once dead, you never shall return.”

Omar Khayyám (1048-1123) Persian poet, mathematician, philosopher, astronomer [عمر خیام]

Rubáiyát [رباعیات], Bod. # 100 [tr. FitzGerald, 3rd ed. (1872), # 35]
    (Source)

The same translation was used by Fitzgerald for the 4th ed. (1879) and 5th ed. (1889).

Where there are numerological references (which multiple sources pull together as variations on this quatrain), they are based on the numbering: One man, two worlds, four elements, five senses, seven planets, eight heavens, nine spheres, ten powers.

Alternate translations:

Lip to lip I passionately kissed the bowl,
To learn from it the secret of length of days;
Lip to lip in answer it whispered reply,
"Drink wine, for once gone thou shalt never return!"
[tr. Cowell (1858), # 25]

Then to this earthen Bowl did I adjourn
My Lip the secret Well of Life to learn:
And Lip to Lip it murmur'd -- "While you live,
"Drink! -- for once dead you never shall return."
[tr. FitzGerald, 1st ed. (1859), # 34]

Then to the Lip of this poor earthen Urn
I lean'd, the secret Well of Life to learn:
And Lip to Lip it murmur'd -- "While you live,
"Drink! -- for, once dead, you never shall return."
[tr. FitzGerald, 2nd ed. (1868), # 34]

O offspring of the four and five, art puzzled by the four and five? Drink deep, for I have told thee time on time, that once departed, thou returnest no more.
[tr. McCarthy (1879), # 245]

I put my lips to the cup, for I did yearn
The secret of the future life to learn;
And from his lip I heard a whisper drop,
"Drink! for once gone you never will return."
[tr. Whinfield (1882), # 149]

I put my lips to the cup, for I did yearn
The means of gaining length of days to learn;
It leaned its lip to mine, and whispered low,
"Drink! for, once gone, you never will return."
[tr. Whinfield (1883), # 152, elsewhere # 274]

I put my lips to the cup, for I did yearn
The hidden cause of length of days to learn;
He leaned its lip to mine, and whispered low,
"Drink! for, once gone, you never will return."
[tr. Whinfield (188?), # 274]

Slave of four elements and sevenfold heaven,
Who aye bemoan the thrall of these eleven,
Drink! I have told you seventy times and seven,
Once gone, nor hell will send you back, nor heaven.
[tr. Whinfield (1882), #223]

Child of four elements and sevenfold heaven,
Who fume and sweat because of these eleven,
Drink! I have told you seventy times and seven,
Once gone, nor hell will send you back, nor heaven.
[tr. Whinfield (1883), # 431]

Sprung from the Four, and the Seven! I see that never
The four and the Seven respond to thy brain's endeavour --
Drink wine! for I tell thee, four times o'er and more,
Return there is none! -- Once gone, thou art gone for ever!
[tr. M. K. (1888)]

Lip to lip with the jar you know not what is intended
That is to say my lip also was like your lips (employed)
In the end since existence is no longer available
Your lips should be thus employed according to the friendly order.
[tr. Heron-Allen (1897), Calcutta # 227]

In great desire I pressed my lips to the lip of the jar,
To inquire from it how long life might be attained;
It joined its lip to mine and whispered: --
"Drink wine, for, to this world, thou returnest not."
[tr. Heron-Allen (1898), # 100]

With strong desire my lips the cup's lip sought
From it the cause of weary life to learn.
Its lip pressed my lips close and whisperèd: --
"Drink, in this world no moment can return."
[tr. Cadell (1899), # 110]

I prest my lip in yearning to the urn.
Thereby the means of length of life to learn.
And lip to my lip placed it whispered low,
"Drink! For to this world you will ne'er return!"
[tr. Thompson (1906), # 320]

To the jar's mouth my eager lip I press'd,
For Life's Elixir making anxious quest;
It join'd its lip to mine, and whisper'd low --
"Drink wine: thou shalt not wake from thy last rest!"
[tr. Talbot (1908), # 100]

I laid my lip to the lip of the wine-cup in the utmost
desire to seek from it the means of prolonging life.
It laid its lip to my lip and said mysteriously: "During
a whole life I was like thee; rejoice for a while in my company."
[tr. Christensen (1927), # 65]

I placed my lip on the lip of the jug and caught from it
The means of attaining a long life.
The jug then seemed to say to me:
"For a lifetime I have been as you; now, for a while, be my companion."
[tr. Rosen (1928), # 177]

My lip to lip of Jar I close in glee,
In hopes that life eternal I would see;
Then quoth the Jar: Like thee I once have been
For ages, hence a minute breathe with me."
[tr. Tirtha (1941), # 5.29]

Greedily to the bowl my lips I pressed
and asked how might I sue for green old age.
Pressing its lips to mine it muttered darkly:
"Drink up! Once gone, you shall return no more!"
[tr. Graves & Ali-Shah (1967), # 36]

I laid my lip against the pitcher's lip in the extremity of desire, that I might seek from it the means of long life: it laid (its) lip upon my lip and said secretly, "I too was (once) like thee: consort with me for a moment."
[tr. Bowen (1976), # 19, after Heron-Allen]

I pressed my lip upon the Winejar's lip,
And questioned how long life I might attain;
Then lip to lip it whispering replied:
"Drink wine -- this world thou shalt not see again."
[tr. Bowen (1976), # 19]

In the extremity of desire I put my lip to the pot's
To seek the elixir of life:
It put its lip on mine and murmured,
"Enjoy the wine, you'll not be here again."
[tr. Avery/Heath-Stubbs (1979), # 139]

I brought the cup to my lips with greed
Begging for longevity, my temporal need
Cup brought its to mine, its secret did feed
Time never returns, drink, of this take heed.
[tr. Shahriari (1998), literal]

The only secret that you need to know
The passage of time is a one way flow
If you understand, joyously you’ll grow
Else you will drown in your own sorrow.
[tr. Shahriari (1998), figurative]