The first watch then is the earliest time of our life, that is, childhood, the second youth and manhood, but the third represents old age. He then who is unwilling to watch in the first, let him keep even the second. And he who is unwilling in the second, let him not lose the remedies of the third watch, that he who has neglected conversion in childhood, may at least in the time of youth or old age recover himself.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: ubi sup.