4 After these things, you were led to the holy pool of Divine Baptism, as Christ was carried from the Cross to the Sepulchre which is before our eyes. And each of you was asked, whether he believed in the name of the Father, and of the Son, and of the Holy Ghost, and you made that saving confession, and descended three times into the water, and ascended again; here also hinting by a symbol at the three days burial of Christ. For as our Saviour passed three days and three nights in the heart of the earth, so you also in your first ascent out of the water, represented the first day of Christ in the earth, and by your descent, the night; for as he who is in the night, no longer sees, but he who is in the day, remains in the light, so in the descent, as in the night, you saw nothing, but in ascending again you were as in the day.
And at the self-same moment you were both dying and being born; and that Water of salvation was at once your grave and your mother. And what Solomon spoke of others will suit you also; for he said, in that case, There is a time to bear and a time to die; but to you, in the reverse order, there was a time to die and a time to be born; and one and the same time effected both of these, and your birth went hand in hand with your death.
Source: Catechetical Lectures (New Advent)