It may be said that the whole life of men is but one day, according to the parable, and that they who are called by the Master of the vineyard in the morning early, are they who from their childhood were called to do the things of the kingdom of God. They who, after they had come to adolescence, begin to serve God are they who are called about the third hour. They who begin as men fully grown are they who were called at the sixth hour. They who in mature age are converted to the work of God are those of the ninth hour, who after the heat of youth, and before the burden of old age, take on themselves the word of the Lord. And the old, who are near to death, are signified by those called at the eleventh hour to labour in the vineyard.
Since it is the purpose that governs life and not the time, which is scrutinised, and in which a man labours in hope: therefore, to every man who labours earnestly, from the time of his calling, an equal reward will be given. Hence they who were faithful from their childhood, who have laboured much, enduring the temptations and difficulties of youth, are grieved at seeing themselves receive an equal reward of salvation with those standing idle from their childhood till old age: standing as it were idle in unbelief, they have come now for but a brief while to believe and to labour.
– Origen of Alexandria, Commentary on Matthew
Locus Communis 