These are some verses from a long fourteenth-century poem with the first line "Whon men beth muriest at her mele" ('when men are merriest at their meal'), from the Vernon MS. It's on essentially the same theme as this poem from the same manuscript, though with a less philosophical bent: the subject is the changeableness of the world, and the foolishness of trusting to it. The fifth of these verses has often been justly praised; it reminds me of what Walter Hilton says about people who seek worldly riches being like children running after butterflies, who fall and hurt themselves because they're not watching where they're going. And also it reminds me of Peter Pan, but that's not really the same point...
You can find the original, with all its verses, here. I just picked the verses I like best.
1. Whon Men beoþ muriest at heor Mele,
wiþ mete & drink to maken hem glade,
wiþ worschip & wiþ worldlich wele
Þei ben so set, þey conne not sade;
Þei haue no deynte for to dele
Wiþ þinges þat ben deuoutli made,
Þei weene heor honour & heore hele
Schal euer laste & neuer diffade.
But in heor hertes I wolde þei hade,
Whon þei gon ricchest men on array,
Hou sone þat god hem may de-grade,
And sum tyme þenk on ȝusterday.
[When men are merriest at their meal, with meat and drink to make them glad, in high honour and worldly prosperity, they are so placed that they think nothing of serious things. They have no fondness for thinking of serious matters; they believe their honour and their health shall last forever and never fade. I wish they would hold in their hearts, when they are men richest in array, how soon God can bring them to nothing again - and sometimes think on yesterday.]
2. Þis day, as leef we may be liht
Wiþ al þe murþes þat men may vise,
To Reuele wiþ þis buirdes briht,
Vche mon gayest on his gyse;
At þe last, hit draweþ to niht,
Þat slep most make his Maystrise.
Whon þat he haþ ikud his miht,
Þe morwe he boskeþ vp to rise,
Þen al draweþ hem to fantasyse;
Wher he is bi-comen, con no mon say,—
And ȝif heo wuste þei weore ful wise,—
ffor al is tornd to ȝesterday.
[Today we may be gladly be light-hearted, with all the mirths man can devise, to revel with beautiful girls, each man dressed in his best way. At last the night draweth on, when sleep has his domain. When sleep has shown his power, the next day everyone prepares to rise; then everyone begins to wonder, but where the day went, no one can say. If they knew, they would be wise; for all is turned to yesterday.]
3. Whose wolde þenke vppon þis,
Mihte fynde a good enchesun whi
To preue þis world al-wei iwis
Hit nis but fantum and feiri,
Þis erþly Ioye, þis worldly blis
Is but a fikel fantasy;
ffor nou hit is, and nou hit nis,
Þer may no mon þer-inne affy.
Hit chaungeþ so ofte & so sodeynly,
To-day is her, to-morwe a-way.
A siker ground ho wol him gy,
I rede he þenke on ȝuster-day.
[Whoever wishes to think on this may find a good reason how to test this world: always, indeed, it is but phantom and illusion. This earthly joy, this worldly bliss, is but a fickle fantasy, for now it is, and now it is not; no man can put faith in it. It changes so often and so suddenly, today it is here, tomorrow is gone. Whoever wants to provide himself with a solid foundation, I advise him to think on yesterday.]
4. ffor þer nis non so strong in stour,
ffro tyme þat he ful waxen be,
ffrom þat day forþ, euer-vch an hour,
Of his strengþe he leost a quantite;
Ne no buryde so briht in bour,
Of þritti wynter, I enseure þe,
Þat heo ne schal fade as a flour,
Luite and luite leosen hire beute.
Þe soþe ȝe may ȝor-self ise,
Beo ȝor eldres in good fay;
Whon ȝe ben grettest in ȝour degre,
I rede ȝe þenke on ȝesterday.
[There is no man so strong and mighty, that from the time he is fully grown is not, from that day forth, every hour, losing a little of his strength. Nor is there any lady so bright in her chamber, of thirty winters, I assure thee, that shall not fade as a flower, and little by little lose her beauty. The truth you may yourself see by looking at your elders, indeed. When you are greatest in your degree, I advise you, think on yesterday.]
5. I haue wist, sin I cuþe meen,
Þat children haþ bi candel liht
Heor schadewe on þe wal i-sen,
And Ronne þer-after al þe niht;
Bisy a-boute þei han ben
To cacchen hit wiþ al heore miht,
And whon þei cacchen hit, best wolde wene,
Sannest hit schet out of heor siht;
Þe schadewe cacchen þei ne miht,
ffor no lynes þat þei couþe lay.
Þis schadewe I may likne a-riht
To þis world and ȝusterday.
[I have known, since I could remember, how children spot their shadow on the wall in the candlelight, and chase after it all night. They are busy to catch it with all their power, but when they thought they were closest to catching it, the more quickly it shot out of their sight. They could not catch the shadow, for any traps that they could lay. I could liken this shadow, indeed, to this world and yesterday.]
6. Sum men seiþ þat deþ is a þef,
And al vnwarned wol on him stele;
And I sey nay, and make a pref,
Þat deþ is studefast, trewe and lele,
And warneþ vche mon of his greef,
Þat he wol o day wiþ him dele:
Þe lyf þat is to ow so leof,
He wol ȝou reue, and eke or hele;
Þis poyntes may no mon him repele.
He comeþ so baldely to pyke his pray,
Whon men beoþ muryest at heor Mele:
I rede ȝe þenke on ȝusterday.
[Some men say that death is a thief, and will steal on them all unawares; but I say no, and say this as a proof that death is steadfast, true, and loyal: he warns every man, to his grief, that he will deal with him one day. The life that is so dear to you, he will take away from you, and your health too. No man can appeal against him on this point, he comes so boldly to seize his prey. When men are merriest at their meal, I advise you, think on yesterday.]