This is a review of what the most believed religious scripture say about what you need to do, to get what kind of afterlife.

Introduction 

In this post, user:BenefitOfTheDoubt ranked the most important factors for happiness in this life, taking into account effect size, strength of evidence and directness of evidence. They close with the finding that the impact of religion on individual happiness is dwarfed by material considerations. But what about supposed non observable consequences, in the afterlife?

Pascal’s Wager is an argument that if you are unsure whether God exists, it is sensible to live as if God does exist. If you believe and God exists, you go to heaven; if you believe and God does not exist, nothing happens and you are just dead. But if you do not believe and God does exist, you go to hell, and if you do not believe and God does not exist, nothing happens and you are just dead. Because the possible gain from belief is heaven and the possible loss is nothing, belief is presented as the safer choice.

The “many gods” objection says that Pascal’s Wager oversimplifies the choice by acting as if there is only one possible God to believe in. In reality, there are many different gods and religions, all with different rules about what they reward or punish. If you choose to believe in one god, you might still be wrong and risk punishment from another god who expects a different belief.

A common reply is to use consensus. We do this in science: we act on what most experts agree on, even if we don't know the details. In the same way, focusing on the top 5 major religions avoids being stuck considering every possible god.

Yes, if I lived in ancient Rome, the Roman pantheon may have been in the top 5. But instead I live now in time and space for inexplicable reasons (this is called 'the even harder problem of consciousness').

Hinduism 

Polytheistic beliefs like Hinduism pre-dated monotheistic beliefs. The earliest Hindu scripture is the Rig Veda:

 “Where there is eternal light, in that world where the sun has set not, all desires are fulfilled — there make me immortal.”  - Rigveda 9.113.7–11

 “Let not the fire consume your skin nor scatter your limbs. Let your body be united again and go to those who lead holy lives.” - Rigveda 10.16.9

In the Bhagavad Gita, in verses 7:23, Krishna explains “Men of small intelligence worship the demigods, and their fruits are limited and temporary. Those who worship the demigods go to the planets of the demigods, but My devotees ultimately reach My supreme planet.” (per the Hare Krishna translation) or “But finite is the result gained by these men of small minds. Those who worship the deities go to the deities; those who worship Me come to Me” in the Advaita Vedanta translation. 

“Having attained Me, the great souls are no longer subject to rebirth in this miserable world, because they have reached the highest perfection.” (Gita 8.15).

"These hateful, cruel, and vile people—the lowest of humanity - I repeatedly cast into demonic wombs, in the cycle of birth and death." (Gita 16.19)

“Bewildered by false ego, strength, pride, lust, and anger… they fall into the unclean worlds of hell.” (Gita 16.18–20).

Patala and Naraka, which are concepts associated with hell or underworld realms, do not appear in the Vedas or in the Bhagavad Gita. Although the Gita is part of the Mahabharata and dates to the same broad period, it holds a distinct and elevated status within Hinduism. References to Naraka and Patala instead occur in other sections of the Mahabharata and are elaborated further in later Puranic literature, such as the Bhagavata Purana. The descriptions of these realms vary significantly between texts and traditions, and they are therefore generally treated as mythological or symbolic.

Buddhism

The Dhammapada is a recording of the Buddha's words.

“The evil-doer grieves here and hereafter; he grieves and suffers when he sees the evil of his own deeds.” - Dhammapada 15

“The liar goes to the state of woe… he burns in hell.” - Dhammapada 306

“He who torments the innocent will soon come to one of these ten states of suffering… being born in hell, in the animal world, in a ghost realm, in poverty, in disease, in madness, or destruction.” - Dhammapada 137–140

"Some are born in a womb, evildoers go to hell, the virtuous go to heaven, and those free from defilements attain Nirvana.” - Dhammapada 126

"Here he rejoices, hereafter he rejoices. The doer of good rejoices in both worlds. He rejoices and exults, seeing the purity of his deeds.” - Dhammapada 18 (Verse 19)

"Even here he is happy, and after death he is happy - the one who has done good." - Dhammapada 22 

In the most common form of Buddhism today - Mahāyāna Buddhism, a Mahāyāna scripture, the Lotus Sutra (Saddharma Puṇḍarīka Sūtra), also expresses:  "All beings, whether they have faith or not, whether they practice this teaching or not,  whether they slander it or praise it - all shall eventually attain Buddhahood." - Lotus Sutra, Chapter 2

Judaism

The concept of "Heaven" has roots in Greek thought and was later adopted by early believers. It does not appear in the Bible nor earlier Jewish thought. Pascal lived in the 17th century and assumed in his wager infinite bliss of heaven and infinite torment of hell because by his time, those were well established in later Catholic writing. However heaven and hell are not biblical ideas, nor Jewish ideas. 

In the Jewish Tanakh: “Many of those who sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt.” Daniel 12:2

"The righteous of all nations have a share in the World to Come." - Tosefta Sanhedrin 13:2; Babylonian Talmud Sanhedrin 105a.

Righteousness is by adhering to a basic set of ethical principles known as the Noahide Laws. These include prohibitions against murder, theft, idolatry, sexual immorality, blasphemy, and cruelty to animals, along with a requirement to establish systems of justice. 

Christianity

The Gospel of Mark is considered the earliest Gospel by scholars. It could reflect the most authoritative view of what Jesus taught as it was published closest to his life, before theological developments in later Gospels. The good afterlife in Mark is referred to as "the kingdom of God" or "life"::

"it is better for you to enter the kingdom of God with one eye than to have two eyes and to be thrown into hell, where their worm never dies, and the fire is never quenched." Mark 9:47-48 where Jesus is quoting Isaiah: "And they shall go out and look at the dead bodies of the people who have rebelled against me; for their worm shall not die, their fire shall not be quenched, and they shall be an abhorrence to all flesh.". Jesus also distinguished between the Kingdom of God, depicted as an internal, present reality, and the Resurrection, a future event tied to the return of Jesus.

I've made a seperate post on the criteria for salvation in Christianity and the connection with altruism.

Islam

Islam came after Christianity and the Qur'an directly talks about Christianity.

First, an information hazard: "O believers! Do not ask about any matter which, if made clear to you, may disturb you. But if you inquire about what is being revealed in the Quran, it will be made clear to you. Allah has forgiven what was done ˹in the past˺.1 And Allah is All-Forgiving, Most Forbearing."

Qur'an 5:72: "They have certainly disbelieved who say, 'Allah is the Messiah, the son of Mary,' while the Messiah has said, 'O Children of Israel, worship Allah, my Lord and your Lord.' Indeed, he who associates others with Allah – Allah has forbidden him Paradise, and his refuge is the Fire. And there are not for the wrongdoers any helpers."

There are disputes over the interpretation of passages that refer to salvation of those of Abrahamic faiths 'Indeed, the believers, Jews, Christians, and Sabians - whoever ˹truly˺ believes in Allah and the Last Day and does good will have their reward with their Lord. And there will be no fear for them, nor will they grieve.'

Surah Al-Ma'idah (5:72) of the Qur'an says "Indeed, he who associates others with Allah, Allah has forbidden him Paradise, and his refuge is the Fire…”

In the Qur’an, the good afterlife, Jannah, is depicted as follows: Surah Qāf (50:34–35): Enter it in peace. That is the Day of Eternity. They will have whatever they wish therein, and with Us is more.”

Surah Fuṣṣilat (41:30–32): “Do not fear and do not grieve but receive good tidings of Paradise… You will have therein whatever your souls desire and whatever you ask for.”

“Indeed, the criminals will be in the punishment of Hell, abiding eternally. It will not be allowed to subside for them, and they, therein, are in despair.” (Qur’an 43:74–75)