"It is the time of mercy for each and all, since no one can think that he or she is cut off from God's closeness and the power of his tender love," he said, and pointed especially to those who are weak, vulnerable and excluded.
He said it is also a special time of mercy for them "because the poor should feel that they are regarded with respect and concern by others who have overcome indifference and discovered what is essential in life."
Francis said that during the special Nov. 11-13 Jubilee for the Socially Excluded, as all Holy Doors around the world apart from that of St Peter's Basilica were closing, "I had the idea that, as yet another tangible sign of this Extraordinary Holy Year, the entire Church might celebrate, on the Thirty-Third Sunday of Ordinary Time, the World Day of the Poor."
"This would be the worthiest way to prepare for the celebration of the Solemnity of our Lord Jesus Christ, King of the Universe, who identified with the little ones and the poor and who will judge us on our works of mercy," he said, adding that the day would also help both communities and individuals "to reflect on how poverty is at the very heart of the Gospel and that, as long as Lazarus lies at the door of our homes, there can be no justice or social peace."
"This Day will also represent a genuine form of new evangelization which can renew the face of the Church as She perseveres in her perennial activity of pastoral conversion and witness to mercy," he said.
Francis noted that during "an intense" Jubilee Year, "we have received the grace of mercy in abundance."
"Because each of us has experienced at length this loving gaze of God, we cannot remain unaffected, for it changes our lives," he said, encouraging all to become witnesses of mercy.
The Jubilee, he said, "has truly been like a new visitation of the Lord among us."
The Pope placed a strong emphasis on the topic of forgiveness throughout the document, as well as the need to look forward and continue the Jubilee path "with joy, fidelity and enthusiasm, experiencing the richness of God's mercy."
Mercy ought to be "celebrated," he said, above all in the liturgy and in the Sacraments, particularly those of penance and the anointing of the sick, as well as in scripture and, for priests, in their homilies.
He spoke of the importance of showing compassion and consolation to others, and offered a special word of closeness to families and married couples amid the various challenges they face.
"We have to remember each of us carries the richness and the burdens of our personal history; this is what makes us different from everyone else," he said.
"Our life, with its joys and sorrows, is something unique and unrepeatable that takes place under the merciful gaze of God."
Pope Francis also spoke of the importance of mercy at the time of death, which is often trivialized "to the point of treating it as an illusion or hiding it from sight."
"Yet death must be faced and prepared for as a painful and inescapable passage, yet one charged with immense meaning, for it is the ultimate act of love towards those we leave behind and towards God whom we go forth to meet," he said, and emphasized the importance of the priest in sharing in this moment.
He also placed a strong emphasis on practicing the corporal and spiritual works of mercy, which he said are "proof of mercy's immense positive influence as a social value" in modern society.
Mercy, he said, "impels us to roll up our sleeves and set about restoring dignity to millions of people; they are our brothers and sisters who, with us, are called to build a city which is reliable."
While many signs of mercy were carried out during the Jubilee, "this is not enough," he said.
"Our world continues to create new forms of spiritual and material poverty that assault human dignity." Because of this, "the Church must always be vigilant and ready to identify new works of mercy and to practise them with generosity and enthusiasm."
Francis encouraged the faithful to "make every effort" to come up with both "specific and responsible" ways of practising charity and the works of mercy.
"Mercy is inclusive and tends to expand in a way that knows no limits. Hence we are called to give new expression to the traditional works of mercy," he said.
He closed his letter by looking to Mary, "who always looks upon us with her eyes of mercy."
"Let us trust in her maternal assistance and follow her perennial counsel to look to Jesus, the radiant face of God's mercy."