It is an expression for a painful place or moment that we have to transit, in a broad sense is our passage through life. It comes from the religious realm, in the Old Testament we find "Passing through the Valley of Baca ( "Valley of Tears") make it a spring, also the early rains cover it with blessings" (Psalm 84 : 6 ). But the real origin of the speech is in the Salve of the Catholic liturgy: "God save you, Queen and Mother of Mercy, life, sweetness and hope of ours. God save you. We cry to you, the banished sons of Eve; we sigh, moaning and crying in this valley of tears."
