In his audience talk to about 15,000 people in St. Peter's Square, Pope Benedict spoke about praising God for his everlasting love, an attitude reflected in Psalm 136.

The psalm praises "God's mighty deeds in the creation of the world and in the history of Israel," saving his people from their enemies and leading them to the Promised Land, the pope said.

After each recollection of something God has given or done for his people, the psalm repeats the refrain "God's love endures forever."

Human history has been marked by periods of darkness and light, and the lives of individuals, too, have been colored by difficulties and great happiness, the pope said.

While it may be hard to imagine the difficulties endured by the early Israelites as recounted in the Psalms, there are plenty of recent episodes in history like the "dark period of Nazi and Communist persecution," the pope said.

No matter how dark the world got, "God came to us, he showed he is good, has strength and that his mercy lasts forever," he said.

"One can survive in these valleys of darkness and death because one remembers the Lord's goodness, power and mercy" never dies and that enduring love -- that light -- acts like a guiding star leading out of the darkness toward hope, he said.

Everybody has a personal experience of salvation and that experience of God's mercy must always be remembered in order to hold strong to one's trust in God and know that "if today I am in the darkness of night, tomorrow I will be free because his mercy is forever," the pope said.

At the end of the audience, Bishop Arthur Roche of Leeds, England, presented the pope the British version of the new English translation of the Roman Missal, the book of prayers used for Mass.

Bishop Roche, chairman of the International Commission on English in the Liturgy, opened the missal to a page of colorful illustrations, and the pope then leafed through the heavy, white leather-bound, gilt-edged missal.