To summarize, then, the Catholic celebration of the Feasts of All Saints and All Souls: what is most obvious during these days of the darkening period of the year is the irruption of the divine on the human scene, multitudes of the saints surrounding the throne of God in heaven as described in the Reading at Mass and then, on the following day, the preoccupation with the dead, another department of the otherworld. Perhaps there is no time in the whole of the liturgical year that we are so obsessed with the otherworld than on those two days--and this was the time in which the pagan Celts were most obsessed with the otherworld also. Even for the Catholics, if the barriers separating the two worlds weren't entirely removed, they have to some extent crumbled. (Sean O Duinn, OSB, Where Three Streams Meet: Celtic Spirituality, Dublin: The Columba Press, pp. 258-259)
...Many songs they knew who now are silent.
Into their memories the dead are gone
Who haunt the living in an ancient tongue
Sung by old voices to the young,
Telling of sea and isles, of boat and byre and glen;
And from their music the living are reborn
Into a remembered land,
To call ancestral memories home
And all that ancient grief and love our own.
(The great Celtic poet, Kathleen Raine)