The idea that "souls" go to heaven at death originated in pagan religion, not the Bible. A brief look at ancient history reveals that the people of Babylon, Egypt, and other kingdoms imagined such an afterlife.
According to This Believing World, by Lewis Browne, the Egyptian god Osiris was thought to have been killed, resurrected and taken to heaven: "Osiris came to life again! He was miraculously resurrected from death and taken up to heaven; and there in heaven, so the myth declared, he lived on eternally" (1946, p. 83).
Browne explains: "The Egyptians reasoned that if it was the fate of the god Osiris to be resurrected after death, then a way could be found to make it the fate of man, too...The bliss of immortality that had formerly been reserved only for kings was then promised to all men...The heavenly existence of the dead was carried on in the realm of Osiris, and it was described in considerable detail by the Egyptian theologians. It was believed that on death the soul of a man set out at once to reach a Judgment Hall on high...and stood before the celestial throne of Osiris, the Judge. There it gave account of itself to Osiris and his forty-two associate gods" (p. 84).
If able to satisfy the gods, "the soul was straightway gathered into the fold of Osiris. But if it could not, if it was found wanting when weighed in the heavenly balances, then it was cast into a hell, to be rent to shreds of the 'Devouress.' For only the righteous souls, only the guiltless, were thought to be deserving of life everlasting" (pp. 86-87).
This idea of men being able to follow their savior-god into heaven was a central focus of the ancient mystery religions. Browne continues: "Mankind everywhere, in Mexico and Iceland, in Zululand and China, makes more or less the same wild guesses in its convulsive effort to solve the riddle of existence...
"In very early times that idea flourished not alone among the Babylonians and Egyptians, but also among the barbaric tribes in and around Greece...These mysteries [came] down from Thrace or across the sea from Egypt and Asia Minor...They declared that for every man, no matter how poor or vicious, there was a place in heaven. All one had to do was to be 'initiated' into the secrets of the cult...then salvation was assured him, and no excess of vice and moral turpitude [i.e., depravity] could close the gates of paradise in his face. He was saved forevermore" (pp. 96-99).
Man has always wanted to live without ever dying. This world and all it offers has never satisfied humanity. For centuries mankind has searched for security and happiness in the hope of going to heaven at death. Regrettably, too many have embraced beliefs that cannot be proven true.
God alone knows the answers to the mysteries of life and death, and He reveals them in His Word, the Holy Bible. Contrary to what so many think, God does not promise eternity in heaven as the reward of the saved. Instead, Jesus says those who overcome will reign with Him in the coming Kingdom of God, which will be established on earth at His return (Revelation 3:21 Revelation 3:21To him that overcomes will I grant to sit with me in my throne, even as I also overcame, and am set down with my Father in his throne.
American King James Version×; Revelation 5:10 Revelation 5:10And have made us to our God kings and priests: and we shall reign on the earth.
American King James Version×; Revelation 11:15 Revelation 11:15And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign for ever and ever.
American King James Version×). Ultimately, they will inherit the entire universe and spirit realm as coheirs with Christ (compare Romans 8:17 Romans 8:17And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together.
American King James Version×; Hebrews 1:1-2 Hebrews 1:1-2  God, who at sundry times and in divers manners spoke in time past to the fathers by the prophets,  Has in these last days spoken to us by his Son, whom he has appointed heir of all things, by whom also he made the worlds;
American King James Version×; Hebrews 2:5-11 Hebrews 2:5-11  For to the angels has he not put in subjection the world to come, whereof we speak.  But one in a certain place testified, saying, What is man, that you are mindful of him? or the son of man that you visit him?  You made him a little lower than the angels; you crowned him with glory and honor, and did set him over the works of your hands:  You have put all things in subjection under his feet. For in that he put all in subjection under him, he left nothing that is not put under him. But now we see not yet all things put under him.  But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honor; that he by the grace of God should taste death for every man.  For it became him, for whom are all things, and by whom are all things, in bringing many sons to glory, to make the captain of their salvation perfect through sufferings.  For both he that sanctifies and they who are sanctified are all of one: for which cause he is not ashamed to call them brothers,
American King James Version×; Revelation 21:7 Revelation 21:7He that overcomes shall inherit all things; and I will be his God, and he shall be my son.
American King James Version×).