The whole idea of the ‘Day of the Dead’ was borrowed from German Pagans and adopted by Roman Catholics and later all minor Churches and congregations having no theological understanding gradually fall in the line.
All Souls’ Day, in Roman Catholicism, a day for the commemoration of all the faithful departed, those baptized Christians who are believed to be in purgatory because they died with the guilt of lesser sins on their souls. It is observed on November 2. Roman Catholic doctrine holds that the prayers of the faithful on earth will help cleanse these souls in order to fit them for the vision of God in heaven, and the day is dedicated to prayer and remembrance.[https://www.britannica.com/topic/All-Souls-Day-Christianity]
The Doctrine of Purgatory is an essential part of Catechism.
a Catholic tradition that, God revealed to St. Gertrude the Great, a 13th-century German Benedictine nun that the following prayer would release 1,000 souls from purgatory every time it is said:
Eternal Father, I offer Thee the Most Precious Blood of Thy Divine Son, Jesus, in union with the Masses said throughout the world today, for all the Holy Souls in Purgatory, for sinners everywhere, for sinners in the universal church, those in my own home and within my family. Amen.
Catholic Online quoted the following:
All Souls Day is a holy day set aside for honoring the dead. The day is primarily celebrated in the Catholic Church, but it is also celebrated in the Eastern Orthodox Church and a few other denominations of Christianity. The Anglican church is the largest protestant church to celebrate the holy day. Most protestant denominations do not recognize the holiday and disagree with the theology behind it.
According to Catholic belief, the soul of a person who dies can go to one of three places. The first is heaven, where a person who dies in a state of perfect grace and communion with God goes. The second is hell, where those who die in a state of mortal sin are naturally condemned by their choice. The intermediate option is purgatory, which is thought to be where most people, free of mortal sin, but still in a state of lesser (venial) sin, must go.
Purgatory is necessary so that souls can be cleansed and perfected before they enter into heaven. There is a scriptural basis for this belief. The primary reference is in 2 Maccabees, 12:26 and 12:32. “Turning to supplication, they prayed that the sinful deed might be fully blotted out… Thus made atonement for the dead that they might be free from sin. [https://www.catholic.org/saints/allsouls/]
Maccabees was not canonical Book even 50 years ago. “Purgatory” is derived from the Latin purgatio which means “cleansing” or “purifying”
Some people say about the following Psalm:
Psalm 51:6-10 reads:
Behold, thou desirest truth in the inward being;
therefore teach me wisdom in my secret heart.
Purge me with hyssop, and I shall be clean;
wash me, and I shall be whiter than snow.
Fill me with joy and gladness;
let the bones which thou hast broken rejoice.
Hide thy face from my sins,
and blot out all my iniquities.
Create in me a clean heart, O God,
and put a new and right spirit within me
The above was applicable for the follower of LAW of MOSES and not a Baptised person in the name of TRINITY.
Sin[Biblical] was correlated with the observation of the Law of Moses or more specifically observation of Deuteronomy injunctions.
The Incarnation of Jesus and his Sacrifice for the Sin of the Sons and Daughters of Adam/Eve, resultant in the forgiveness of Humanity is the essence of the Ministry of Jesus and the marrow of the Gospel. Through the person and act of the Christ, God the Father entered into a new contract [Novam Testamentum] with the Humanity abolishing the previous contracts[Vetus Testamentum] with Adam, Noa, Jacob, Moses, Devid, and Daniel.
Therefore, in reality, every believer is already completely holy in God’s sight as a result of the Savior’s sacrifice on the cross 2000 years ago. This complete cleansing flows from the miracle of the cross. (1 Peter 2:24,25) Thankfully, every Christian is already “seated with Christ in the heavenly realms.” (Eph. 2:6) The complete purification of a sinner’s soul occurs the moment the new birth takes place (John 3:6,7) in a person’s heart through faith in Christ. (John 1:12; John 3:16)
“We have been made holy through the sacrifice of the body of Jesus Christ once for all.” (Hebrews 10:10) [https://www.christianpost.com/voice/why-purgatory-is-a-dangerous-doctrine.html]
So the intermediate state of the soul is a Vogus Doctrine.
At the Council of Florence (1449) the Greek Church laid down the idea as one of the irreconcilable differences between them and the Latin church.
The Cathari, the Waldensia, Wyclif and Luther opposed the doctrine.
The teaching of the Greek Catholic Church is as stated in their catechism, “The Longer Catechism” (adopted 1839; cfr. Schaff, Creeds, ii. 504).
Q. 376. What is to be remarked of such souls as have departed with faith, but without having had time to bring forth fruits worthy of repentance?
This, that they may be aided toward the attainment of a blessed resurrection by prayers offered in their behalf, especially such as are offered in union with the oblation of the bloodless sacrifice of the Body and Blood of Christ, and by works of mercy done in faith for their memory.
Q. 377. On what is this doctrine grounded?
On the constant tradition of the Catholic Church, the sources of which may be seen even in the Church of the Old Testament. Judas Maccabaeus offered sacrifices for his men that had fallen (II Macc. xii 43) Prayer for the departed has ever formed a fixed part of the divine Liturgy, from the first Liturgy of the apostle James. St. Cyril of Jerusalem says, “Very great will be the benefit to those souls for which prayer is offered at the moment when the holy and tremendous sacrifice is laying in view.” (“Mystagogical Lectures,” v.9). St. Basil the Great, in his Prayers for Pentecost, says that “the Lord vouchsafes to receive from us propitiatory prayers and sacrifices for those that are kept in Hades, and allows us the hope of obtaining for them peace, relief, and freedom.”
The Roman Catholic doctrine is as follows (Schaff, Creeds, ii. 198-199:
Whereas the Catholic Church, instructed by the Holy Ghost, has, from the Sacred Writings and the ancient tradition of the Fathers, taught in sacred councils, and very recently in this ecumenical synod, that there is a purgatory, and that the souls there detained are helped by the suffrages of the faithful, but principally by the acceptable sacrifice of the altar: the holy synod enjoins on bishops that they diligently endeavor that the sound doctrine concerning purgatory…be believed, maintained, taught, and everywhere proclaimed by the faithful of Christ.
The difference between Eastern Orthodox and Roman Catholics are visible enough.
Accepting Purgatory is Denial of Christ
1:29 The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world [Gospel of John]
The monologue of Jesus demolishes the satanic doctrine of purgatory and all souls`day
17:13 And now come I to thee; and these things I speak in the world, that they might have my joy fulfilled in themselves.
17:14 I have given them thy word; and the world hath hated them, because they are not of the world, even as I am not of the world.
17:15 I pray not that thou shouldest take them out of the world, but that thou shouldest keep them from the evil.
17:16 They are not of the world, even as I am not of the world.
17:17 Sanctify them through thy truth: thy word is truth.
17:18 As thou hast sent me into the world, even so have I also sent them into the world.
17:19 And for their sakes I sanctify myself, that they also might be sanctified through the truth.
17:20 Neither pray I for these alone, but for them also which shall believe on me through their word; 17:21 That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me.
17:22 And the glory which thou gavest me I have given them; that they may be one, even as we are one: 17:23 I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me.
17:24 Father, I will that they also, whom thou hast given me, be with me where I am; that they may behold my glory, which thou hast given me: for thou lovedst me before the foundation of the world.
17:25 O righteous Father, the world hath not known thee: but I have known thee, and these have known that thou hast sent me.
17:26 And I have declared unto them thy name, and will declare it: that the love wherewith thou hast loved me may be in them, and I in them. [ Gospel of John]