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 5:10; Revelation 11:15). Ultimately, they will inherit the entire universe and spirit realm as coheirs with Christ (compare Romans 8:17; Hebrews 1:1-2; Hebrews 2:5-11; Revelation 21:7).