Luke 12:38

Our Lord knew the proneness of human infirmity to sin, but because He is merciful, He docs not allow us to despair, but rather has compassion, and gives us repentance as a saving remedy. And therefore He adds, And if he shall come in the second watch, &c. For they who keep watch on the walls of cities, or observe the attacks of the enemy, divide the night into three or four watches. Of the first watch, however, he makes no mention, for childhood is not punished by God, but obtains pardon; but the second and third age owe obedience to God, and the leading of an honest life according to His will.

(ubi sup.) 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.

Or since the watches are the hours of the night which lull men to sleep, you must understand that there are also in our life certain hours which make us happy if we are found awake. Does any one seize your goods? Are your children dead? Are you accused? But if at these times you have done nothing against the commandments of God, He will find you watching in the second and third watch, that is, at the evil time, which brings destructive sleep to idle souls.

(Severus.) Or, to the first watch belong those who live more carefully, as having gained the first step, but to the second, those who keep the measure of a moderate conversation, but to the third, those who are below these. And the same must be supposed of the fourth, and if it should so happen also of the fifth. For there are different measures of life, and a good rewarder metes out to every man according to his deserts.