Preface
Asking some mercy for the departed is a movement of a loving heart, that is, of a person guided by love for God and neighbor. We do not know how the Lord will decide to act with regard to this or that petition for the departed, yet we have a reason for hope and a love that moves us to care. What is this reason? The reason is divine revelation, from which we learn that God is almighty, that He holds the “keys” of Hades and death, that there are sins which will not be forgiven even in the age to come (which allows us to understand that there are other sins too), and that God has called us to turn to Him with the most varied petitions. We also know that the measure of punishment of sinners is not the same, and the degree of blessedness of the righteous is not the same, therefore even if a person is not saved, we hope for a softening of his lot. The departed were cared for in the Old Testament (see below), and the most ancient Christians cared for them too (more).
To all this we are moved by love, which “never fails” (1 Cor. 13:8).
God Is Almighty
“Behold, I am the LORD, the God of all flesh. Is there anything too hard for Me?” (Jer. 32:27)
Other quotes: https://bibleox.com/en/en/w/iVKa_God_Almighty
God Promised That Those Who Keep the Commandments Will Receive in Prayer Whatever They Ask with Faith
“And whatever we ask we receive from Him, because we keep His commandments and do those things that are pleasing in His sight” (1 John. 3:22)
“And if we know that He hears us, whatever we ask, we know that we have the petitions that we have asked of Him” (1 John. 5:15)
“And whatever things you ask in prayer, believing, you will receive” (Matt. 21:22)
“Again I say to you that if two of you agree on earth concerning anything that they ask, it will be done for them by My Father in heaven” (Matt. 18:19)
“You did not choose Me, but I chose you and appointed you that you should go and bear fruit, and that your fruit should remain, that whatever you ask the Father in My name He may give you” (John. 15:16)
These words are said in the context of prayer for the salvation of sinning brothers, whom God saves through the prayer of the righteous:
“And if we know that He hears us, whatever we ask, we know that we have the petitions that we have asked of Him. If anyone sees his brother sinning a sin which does not lead to death, he will ask, and He will give him life for those who commit sin not leading to death. There is sin leading to death. I do not say that he should pray about that” (1 John. 5:15-16)
Sins Can Be Forgiven Through the Prayer of the Church
This means that sins are forgiven not only when the person himself repents and asks for forgiveness, but also when others ask for the forgiveness of his sins:
“Is anyone among you sick? Let him call for the elders of the church, and let them pray over him, anointing him with oil in the name of the Lord. And the prayer of faith will save the sick, and the Lord will raise him up. And if he has committed sins, he will be forgiven” (James. 5:14-15)
The friends of a paralyzed companion labored hard to bring their friend to Christ. And by their faith the Lord forgave the paralytic his sins and healed him:
“When Jesus saw their faith, He said to the paralytic, ‘Son, your sins are forgiven you’” (Mark. 2:5)
Sins Can Be Forgiven Even After Death
It follows from the words of the Lord Jesus Christ that the forgiveness of sins is possible not only in this age, but also in the age to come. There are sins that will be forgiven neither now nor later:
“Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men. Anyone who speaks a word against the Son of Man, it will be forgiven him; but whoever speaks against the Holy Spirit, it will not be forgiven him, either in this age or in the age to come” (Matt. 12:31-32).
Christ Holds the Keys of Hades and Death
“And when I saw Him, I fell at His feet as dead. But He laid His right hand on me, saying to me, ‘Do not be afraid; I am the First and the Last. I am He who lives, and was dead, and behold, I am alive forevermore. Amen. And I have the keys of Hades and of Death’” (Rev. 1:17-18)
The Old Testament. Care for the Forgiveness of the Sins of the Departed
Fasting for the Departed
The Israelites fasted for the dead King Saul, his sons and all the Israelites who fell in battle
“So Saul, his three sons, his armorbearer, and all his men died together that same day” (1 Sam. 31:6)
“Then they took their bones and buried them under the tamarisk tree at Jabesh, and fasted seven days” (1 Sam. 31:13)
“And they mourned and wept and fasted until evening for Saul and for Jonathan his son, for the people of the LORD and for the house of Israel, because they had fallen by the sword” (2 Sam. 1:12)
Prayer and Sacrifice for the Departed
The Jews prayed for the fallen warriors, that their sin might be forgiven. They also sent money to the Temple in Jerusalem, so that a sacrifice of atonement might be offered for the dead, for their cleansing from sin:
“Then Judas assembled his army and went to the city of Adullam. As the seventh day was coming on, they purified themselves according to the custom, and kept the sabbath there. On the next day, as had now become necessary, Judas and his men went to take up the bodies of the fallen and to bring them back to lie with their kindred in the sepulchres of their ancestors. Then under the tunic of each one of the dead they found sacred tokens of the idols of Jamnia, which the law forbids the Jews to wear. And it became clear to all that this was the reason these men had fallen. So they all blessed the ways of the Lord, the righteous judge, who reveals the things that are hidden; and they turned to supplication, praying that the sin that had been committed might be wholly blotted out. The noble Judas exhorted the people to keep themselves free from sin, for they had seen with their own eyes what had happened as the result of the sin of those who had fallen. He also took up a collection, man by man, to the amount of two thousand drachmas of silver, and sent it to Jerusalem to provide for a sin offering. In doing this he acted very well and honorably, taking account of the resurrection. For if he were not expecting that those who had fallen would rise again, it would have been superfluous and foolish to pray for the dead. But if he was looking to the splendid reward that is laid up for those who fall asleep in godliness, it was a holy and pious thought. Therefore he made atonement for the dead, so that they might be delivered from their sin” (2 Macc. 12:38-45)
Almsgiving for the Departed
The Jews gave alms for the sake of the departed:
“Give graciously to all the living; do not withhold kindness even from the dead” (Sir. 7:33)
“Place your bread on the grave of the righteous, but give none to sinners” (Tob. 4:17)
Alms for the dead were not given from the tithe:
“When you have finished laying aside all the tithe of your increase in the third year — the year of tithing — and have given it to the Levite, the stranger, the fatherless, and the widow, so that they may eat within your gates and be filled, then you shall say before the LORD your God: ‘I have removed the holy tithe from my house, and also have given them to the Levite, the stranger, the fatherless, and the widow, according to all Your commandments which You have commanded me; I have not transgressed Your commandments, nor have I forgotten them. I have not eaten any of it when in mourning, nor have I removed any of it for an unclean use, nor given any of it for the dead. I have obeyed the voice of the LORD my God, and have done according to all that You have commanded me’” (Deut. 26:12-14)
With God All Are Alive
The quotes given show the beliefs of the Jews and their concrete practices. They prayed for the forgiveness of the sins of the dead, fasted for the dead, offered sacrifices for the dead, gave alms for the dead and in general cared about their lot after death. Only the Sadducees rejected existence after death, and the Lord rebuked them for their errors and their ignorance of the Scriptures:
“Jesus answered and said to them, ‘You are mistaken, not knowing the Scriptures nor the power of God’” (Matt. 22:29)
“He is not the God of the dead, but the God of the living. You are therefore greatly mistaken” (Mark. 12:27)
Hope for Every Help for the Departed
Even if some person could not be saved from hell, in any case his sufferings can be eased, some consolation can be given, now or in the future (after the general resurrection and the Judgment), because the measure of punishment is not the same:
“And that servant who knew his master’s will, and did not prepare himself or do according to his will, shall be beaten with many stripes. But he who did not know, yet committed things deserving of stripes, shall be beaten with few. For everyone to whom much is given, from him much will be required; and to whom much has been committed, of him they will ask the more” (Luke. 12:47-48)
More quotes on the difference in punishment: the measure of punishment is not the same.