Vatican Saying 66 (quoted below) encourages thoughtfulness instead of lamentation. It seems most likely that the saying refers to circumstances in which a friend has died.
In the Epicurean view, sadness at death is alleviated or even removed by the consideration that death is a natural part of the way things are. So long as it is not untimely, death does not prevent us from enjoying a life of happiness and fulfilment, and does not take away from a life well lived.
Epicurus emphasized the possibilities for pleasure and contentment in this life and condemned the wastefulness of allowing fears about death to spoil the enjoyment of life. From the playwright Menander, a contemporary of Epicurus, we have a fragment which reflects a philosophical appreciation for the natural wonders of this life. The following is an adaptation.
I call that person happiest, my friend,
Who has the chance to look upon the sun
That lights us all, to gaze up to the stars,
To see the clouds, and water, and the fire
Of lightning in the sky – these things so great
And grand and wonderful; and who has learned
To live without distress, and known such joys
That one can go as quickly as we come,
To that dispersion whence we all are formed;
Not only we but those things marvellous
That you will see always, though you live
A hundred years or only very few.
And greater things than these you will not see,
Thoughts for the Day, September 21: ‘Let us sympathize with our friends not with wailing but with thoughtfulness’ (Vatican Sayings 66).
Verses: SRP after Menander, fr. 373, from the play The Counterfeit Baby, or The Rustic (Ὑποβολιμαῖος ἢ Ἄγροικος, trans. Allinson). An old edition of the Greek is available online (A. Meineke (ed.), Menandri et Philemonis reliquiae, Berlin, 1823, p. 166, from Stobaeus). A text and translation are given in the Loeb edition of Menander (an older version by F.G. Allinson is available online; the more recent edition by W.G. Arnott should also be consulted). The dramatic context is not exactly Epicurean; it suggests that a short visit is better than a long stay, whereas in the Epicurean view old age has special advantages. I have adapted the sense in a number of ways in an Epicurean direction.