In Islam, there are two distinct stages after death. The first stage is known as the stage of the barzakh or the life of the grave. The other stage is the Day of Judgment and eternal life in Heaven or Hell. Each of these stages has its own distinctive characteristics.
as Muslims, we must never give in to speculation, as people of diverse religions have done, especially matters related to the unseen or ghayb as the unseen world, as far as Islam is concerned, remains forever beyond rational speculation.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following: In Islam there are two areas of knowledge: First, the areas that are subject to human cognition; second, those that are not subject to human cognition. While knowledge of the first category is the subject of observation, experimentation, and empirical standards, the knowledge of the second category is not simply so. Since things in the second category are not subject to the senses, empirical testing and observation, or rational scrutiny, they are known in Islam as matters of the ghayb (Unseen). The matters of ghayb, we are told, are known only to God. Therefore, the only way humans can have any access whatsoever to such matters must be solely through the medium of revelation.

Since matters of the ghayb are veiled from us, the only knowledge that we can gain concerning them comes through God’s own disclosure through His chosen messengers and revealed scriptures. The Qur’an claims to be the final one, confirming the truths revealed to all prophets and containing a full exposition of all things that humans need for guidance. What we know from the Qur’an is that man’s life does not end with death but continues after.
there are two distinct stages beyond death: The first stage is that of barzakh, the life of the grave, and the other is Judgment Day and eternal life in Heaven or Hell. Each of these stages is different from the other, just as they are different from the stages that humans have passed through prior to their death.
all [revealed] religions agree on the basic notion of Heaven and Hell; but they differ in their precise articulation of their nature and content. The difficulty is that human knowledge is not simply meant to depict or describe the nature of eternal life or Heaven or Hell; at best, what we are given in the scripture about such matters can be considered as reminders and approximations, nothing more. How can language, which has been created to describe the things of the limited world, be used to describe the experience of eternal life, which is beyond all comparison? Allah said, (No soul knows what is kept hidden for them of delights of eyes, as a reward for what they used to do) (As-Sajdah: 32:17). The Prophet (peace and blessings be upon him) is reported to have said, “In the Heaven there will be such bliss the like of no eye has ever witnessed, no ears have heard about, nor any mind has ever conceived.” (Reported by At-Tabarani)
If Heaven is utmost bliss, then Hell is the utmost suffering, pain, and misery—beside which, all of the troubles of this world would seem utterly insignificant.
the differences among religions in describing Heaven and Hell have more to do with speculation and theology, rather than revelation. As Muslims, we must never give in to speculation, as people of diverse religions have done, especially in regards to matters of the ghayb, which must remain forever beyond rational speculation. So never give much importance to such theologies. Focus on the idea of the existence of these realms, and internalize these concepts and beliefs deeply. When we do so, Allah will grant us an experiential certainty. As the Prophet asked one of his Companions, “What is the reality of your faith?” He replied, “It is as though I see plainly the throne of God in front of me!” The Prophet (peace and blessings be upon him), then told him, “You have attained true knowledge, and, therefore, persevere in it.”
In other words, when a believer believes in Allah and His Messenger and submits to His will earnestly and sincerely, and experiences faith deep within himself or herself, those matters that are veiled become overriding realities and deep convictions that fill the heart and mind. Consequently, the eyes of the heart will be open to attest and testify to the truth of it. That is the only door open to us in regards to such matters.
On the other hand, engaging in idle speculation about the nature of Heaven and Hell and what lies beyond death, and articulating about them in human terms, is a futile endeavor. It will never yield us any beneficial knowledge. As humans, we are better advised to recognize the limitations of human knowledge and know the Qur’anic dictum, (And of the knowledge you have been given but little) (Al-Israa’ 17:85); and (They know only certain appearances of the life of this world, and are unaware of the Hereafter) (Ar-Rum 30:7).
as for the differences among religions with regard to describing the life beyond death, it is due to unwarranted speculation. Concerning such differences, we are told by Allah, (Your Lord shall judge between them on the Day of Resurrection concerning that in which they differ) (As-Sajdah 32:25). (Mankind was only one nation, then they fell into variance; and had it not been for a word that had already gone forth from our Lord, their differences would have been settled between them) (Yunus 10:19). (Those who believe, the Jews, the Sabaeans, the Christians, the Magians, and the Idolaters, Allah will surely judge between them on the Day of Resurrection. And Allah is witness over all things) (Al-Hajj 22:17). (And say, “We believe in that which has been sent down to us and that which has been sent down to you; our God and your God is One, and to Him we surrender) (Al-`Ankabut 29:46). (And if they argue with you, say, “I have surrendered myself to Allah, and (so have) those who follow me.” And say to those who have received the Book and those who read not, “Do you too surrender yourself to Him alone?” If they do, they will be guided, but if they turn away, your only duty is to convey the message. God is aware of His servants) (Aal `Imran 3:20)