All Saints' Day is a solemn holy day of the Catholic Church celebrated annually on November 1st. The day is dedicated to the saints of the Church, that is, all those who have attained heaven. It should not be confused with All Souls' Day, which is observed on November 2nd, and is dedicated to those who have died and not yet reached heaven.
Although millions, or even billions of people may already be saints, All Saints' Day observances tend to focus on known saints --that is those recognized in the canon of the saints by the Catholic Church.
All Saints' Day was formally started by Pope Boniface IV, who consecrated the Pantheon at Rome to the Virgin Mary and all the Martyrs on May 13 in 609 AD. Boniface IV also established All Souls' Day, which follows All Saints. The holy day was eventually established on November 1st by Pope Gregory III in the mid-eighth century as a day dedicated to the saints and their relics. The May 13th celebration was subsequently abandoned.
Catholics celebrate all those who have entered heaven, including saints who are recognized by the Church and those who are not.
Solemnity of All Saints of the Liturgical Calendar is November 1st.
The concept of All Saints Day is connected to the doctrine of The Communion of Saints. This is Catholic teaching that all of God's people, on heaven, earth, and in the state of purification (Purgatory), are spiritually connected and united. In other words, Catholic and Orthodox Christians (and some Protestants) believe that the saints of God are just as alive as those on earth, and are constantly interceding on our behalf. Our connection with the saints in heaven is grounded in a tight-knit communion. The saints are not divine, nor omnipresent or omniscient like God is. However, because of our common communion with and through Jesus Christ, our prayers are joined with the heavenly community of Christians. Saint Cyril of Jerusalem (AD 350) testifies to this belief:
We mention those who have fallen asleep: first the patriarchs, prophets, apostles, and martyrs, that through their prayers and supplications God would receive our petition...(Catechetical Lecture 23:9).
The Catholic Catechism concisely describes this communion among believers, by which we are connected to Christ, and thus to one another:
"Being more closely united to Christ, those who dwell in heaven fix the whole Church more firmly in holiness...They do not cease to intercede with the Father for us...So by their fraternal concern is our weakness greatly helped."
"...as Christian communion among our fellow pilgrims brings us closer to Christ, so our communion with the saints joins us to Christ, from whom as from its fountain and head issues all grace, and the life of the People of God itself: We worship Christ as God's Son; we love the martyrs as the Lord's disciples and imitators, and rightly so because of their matchless devotion towards their king and master. May we also be their companions and fellow disciples (CCC 956, 957)!
There are thousands of canonized saints, that is those individuals officially recognized by the Church as holy men and women worthy of our imitation. Because miracles have been associated with them, and their lives have been fully examined and found holy by the Church, we have assurance they are prime examples of holiness, and powerful intercessors before God on our behalf.
- churchyear.net
Because we are joined to those who have gone before us through the Communion of Saints, we can call upon the faithful departed for their interissory prayers for our intentions here on earth.
The Church, in her prayers and liturgies, frequently asks for the intercesion of the saints and those faithful who have gone before us into the next fe (cf. CCC 957-958, 2647). This pious practice pertains to the doctrine of the Communion of Saints, through which the faithful on earth (the Church Militant) are united as one body with the faithful in Purgatory (the Church Suffering) and the blessed in Heaven (the Church Triumphant). Devotion the saints corresponds in its very essence to the profound reality of the Church as a mystery of communion. (Cf. CCC 948, 961,1476)
We believe in the communion of all the faithful of Christ, those who are pilgrims on earth, the dead who are being purified, and the blessed in heaven, all together forming one Church; and we believe that in this communion, the merciful love of God and his saints is always [attentive]
to our prayers. (Bl. Paul VI, CPG 30; cf. CCC 962)
By reason of the fact that those in heaven are more closely united with Christ, they establish the whole Church more firmly in holiness....They do not cease to intercede with the Father for us, showing forth the merits which they won on earth through the one Mediator between God and man (cf. 1 Tm 2:5).... Thus by their brotherly interest our weakness is greatly strengthened. (LG 49)
Just as we ask for prayers from those on earth who have a close relationship with God, we likewise ask for the intercession of saints because we know they are united with Christ. (Cf. CCC 2683)
It is supremely fitting, therefore, that we love those friends and coheirs of Jesus Christ, who are also our brothers and extraordinary benefactors, that we render due thanks to God for them and suppliantly invoke them and have recourse to their prayers, their power and help in obtaining benefits from God through His Son, Jesus Christ, who is our Redeemer and Saviour. (DS 1821; LG 50)
The saints are not a small caste of chosen souls but an innumerable crowd to which the liturgy urges us to raise our eyes. This multitude not only includes the officially recognized saints, but the baptized of every epoch and nation who sought to carry out the divine
will faithfully and lovingly. We are unacquainted with the faces and even the names of many of them, but with the eyes of faith we see them shine in God's firmament like glorious stars.
But "why should our praise and glorification, or even the celebration of this solemnity, mean anything to the saints?" A famous homily of Saint Bernard begins with this question, and the response he offers us is timely:
"The saints," he says, "have no need of honor from us; neither does our devotion add the slightest thing to what is theirs. But I tell you, when I think of them, I feel myself inflamed by a tremendous yearning."
This, then, is the meaning of today's solemnity: looking at the shining example of the saints to reawaken within us the great longing to be like them; happy to live near God, in his light, in the great family of God's friends.
Being a saint means living close to God, to live in his family. And this is the vocation of us all. But how can we become holy, friends of God? We can first give a negative answer to this question: to be a saint requires neither extraordinary actions or works nor the possession of exceptional charisms. Then comes the positive reply: it is necessary first of all to listen to Jesus and then to follow him without losing heart when faced by difficulties.
Like the grain of wheat buried in the earth, those who trust him and love him sincerely accept dying to themselves. Indeed, he knows that whoever seeks to keep his life for himself loses it, and whoever gives himself, loses himself, and in this very way finds life. The saints' biographies describe men and women who, docile to the divine plan, sometimes faced unspeakable trials and suffering, persecution and martyrdom. They persevered in their commitment. Their names are written in the book of life and heaven is their eternal dwelling place. The example of the saints encourages us to follow in their same footsteps and to experience the joy of those who trust in God. In the Preface of the Mass we will proclaim that the saints are friends and models of life for us. Let us invoke them so that they may help us to imitate them and strive to respond generously, as they did, to the divine call. In particular let us invoke Mary, Mother of the Lord and mirror of all holiness. May she, the All Holy, make us faithful disciples of her Son Jesus Christ! Amen.
-Pope Benedict XVI
His Holiness Benedict XVI served as pope from 2005 until 2013.