Quatrain 28

Myself when young did eagerly frequent
Doctor and Saint, and heard great argument
About it and about: but evermore
Came out by the same door where in I went.

FitzGerald, Stanza XXVII, 4th ed.

Heron-Allen (p. 45) asks us to consider Stanza XXVIII along with XXVII:

With them the seed of Wisdom did I sow,
And with my own hand wrought to make it grow:
And this was all the Harvest that I reap'd

"I came like Water, and like Wind I go."

FitzGerald, Stanza XXVIII, 4th ed.

And a source-quatrain from the Bodleian or Ouseley MS 121, Heron-Allen, p. 45:

یکچند بکودکی باستاد شدیم
یکچند باستادی خود شاد شدیم
پایان سخن نگر که ما را چه رسید
چون آب درآمدیم و چون باد شدیم

yekchand bekudaki beostaad shodim
yekchand beostaadi-ye khod shaad shodim
paayaan-e sokhan negar ke maa raa che rasid
chon aab daraamadim o chon baad shodim
Heron-Allen, p. 45, from the Bodleian/Ouseley MS, 121

For a while in childhood we attended a master;
for a while we were happy with our own mastery;
at the end of the story see what happened to us--
like water we entered, and like the wind we departed.

Arberry, Romance ... 209

When a child I followed my teacher,
then I became my teacher myself--
Here's the gist of all I have learned:
"We drift into life -- wind takes us away." 

For the Bodleian MS itself and the many renditions, select this link from omariana.nl

Notes: This quatrain also appears in Dashti (27), Hedaayat (37), Forughi-Ghani (134), Saidi (134), Whinfield (334).  Variations occur in the third line, where all but Dashti read shenow, شنو, "hear" instead of نگرnegar, "see". And in the fourth mesraa the Ouseley MS reads  (of course) as above and Hedaayat's reads like this as well.  The others have: az khaak bar/daraamadim o bar baad shodim, از خاک بر/درآمدیم و بر باد شدیم - "we come from dust and we go on the wind" (although it makes little difference, the verbs in the third and fourth lines are "aphoristic pasts" and should be translated as presents).  "We come from dust..." is more doctrinally correct if I can put it this way.  Saidi's note (105, p. 253) refers us to the Qur'an, 23.12: "We created man from clay ..."

FitzGerald's Latin sketch:

Aliquando cum Doctore sapienter seminabam,
Aliquando proprio Doctrinae cultû laborabam,
Ergo tantae nunc Doctrinae messem ultimum conscribo--
Unda velut hic adveni, Aura velut hinc abibo.

For a time I was wise to confer with a teacher,
For a time I went forward nurturing what I had learned,
And now I sum up this great harvest of learning:
As I came on a wave, so I go on the wind.

As you see, FG used the Ouseley MS, rather the last two lines of  O 121, for Stanza XXVIII.  What about XXVII? Heron-Allen (p. 45) offers up Calcutta 281, for which the last two lines, the last especially, conform to Stanza XXVII:

اینجا چو نیافتم کس[ی] محرم راز
زان در که درآمدم  برون رفتم باز

injaa cho nayaaftam kas[i] mahram-e raaz
zaan dar ke daraamadam berun raftam baaz

Being once a falcon, I flew from the World of mystery.
That from below I might soar to the heights above;
But not finding there any intimate friend,
I came out by the same door wherein I went.

Heron-Allen, p.45 with a footnote and an explanation of محرم راز, viz., "partner of the secret"
[to which the traveler had hoped to find on high]

kas is written which should be kasi as I have indicated.