In the Old Testament, under the old covenant of the law, for man, in order to be blessed by the Lord, he has to sacrifice a spotless lamb, symbolic of our Lord Jesus, where the blood of the lamb would cover one's sins for one whole year. We see this in the case of Abel in Genesis 4:4, where Abel came before the Lord by the blood of the lamb, because of which he had the Lord's favor upon him. Whereas Cain came before the Lord by his own works, hence the Lord was not pleased with Cain's offering. We also notice, that during the night of the Passover in Egypt, as stated in Exodus 12:1, the Jews applied the blood of the spotless lamb on their lintels, because of which the people of the household with the blood applied were protected. When the Israelites asked the Lord for the law in Exodus 19:8, the Lord knew that no man would be able to keep God's perfect law without Jesus, hence the Lord had instructed about the offering of the sacrificial lamb. If the Lord wanted to be strict towards man in law keeping, He would have just given the law and stopped. It is because the Lord knew, that man would not be able to keep the law, He instructed Moses, under the Levitical Priesthood, that a person should offer a lamb as a sacrifice, whose blood would cover the person's sins for one whole year, as stated in Leviticus 16:34. The Bible says:
"And almost all things are by the law purged with blood; and without shedding of blood is no remission" - Hebrews 9:22
In other words, the good works of a person cannot justify an individual. The Bible is very clear that without the shedding of blood, the sins of a person cannot be forgiven. This has been the case ever since Adam fell.
If that was the case, then where did the people go when they died under the old covenant of the law?
All the people under the old covenant of the law went to a place called "Paradise", which was initially located at the heart of the earth. When the Jews asked for a sign from our Lord Jesus, as proof, that He is indeed the Messiah, Jesus replied to them in Matthew 12:39-40 by saying, that only one sign would be given to them, and that is, just as prophet Jonah was in the belly of the whale for three days and three nights, so shall Jesus also be in the heart of the earth for three days and three nights. Also, when our Lord was crucified between two thieves, one of them repented and asked the Lord to remember him, to which our Lord Jesus replied saying:
"And Jesus said unto him, Verily I say unto thee, Today shalt thou be with me in paradise" - Luke 32:43
We even hear our Lord Jesus describing about paradise, when he explained about "The Rich man and Lazarus" in Luke 16:19. The Jews called this place as "Abraham's bosom", which was the same place that our Lord Jesus stated as "Paradise" to the repentant thief on the cross. If paradise was in heaven, then that would mean that when Jesus died on the cross, He did not stay in the heart of the earth for three days and three nights, which would contradict Matthew 12:39-40. But God's Word clearly states that Jesus was indeed in the heart of the earth for three days and three nights, and was resurrected on the third day. This clearly states that Paradise and Abraham's bosom is the same place, wherein there was a great gulf fixed between paradise and hell, where people could not come to the other side as described in Luke 16:26. If law keeping had justified the people, then they would have gone to heaven when they died, but the Bible clearly states that law keeping does not justify a person:
"Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin." - Romans 3:20
The above was man's condition before our Lord Jesus shed His precious and eternal Blood, once for all, on the cross of Calvary. Till Jesus's death, burial and resurrection, the Bible does not record the dead going to heaven. Enoch and Elijah were a special case, where they were raptured and taken up to heaven while they were alive. All of them, who were under the old covenant of the law, were waiting for the Messiah, who would shed His Blood and would release them from their captivity, and take them all to heaven by granting them eternal life.
The Good News is, that in the New Testament, our Lord Jesus came as the "Lamb of God", whose Blood does not cover the sins, but rather takes away the sins of the world. This is the reason John the Baptist, when he saw our Lord Jesus, said:
"The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world" - John 1:29
When our Lord Jesus died on the cross, He went to the heart of the earth, and was there for three days and three nights. When He was resurrected on the third day, He took along with Him, all of the people who were under the old covenant of the law, who were in Paradise (Abraham's bosom), and went to heaven and sat at the right hand of God the Father as 100% man, and also as 100% God. The Bible records this first resurrection of the dead in the New Testament as the first fruits:
"For since by man came death, by man came also the resurrection of the dead. For as in Adam all die, even so in Christ shall all be made alive. But every man in his own order: Christ the firstfruits; afterward they that are Christ's at his coming" - 1 Corinthians 15:21-23
Under the old covenant of the law, paradise was located in the heart of the earth. But today, after Jesus's resurrection, paradise which was at the heart of the earth is now moved to heaven. Apostle Paul confirms this to the Corinthian Christians:
"I knew a man in Christ above fourteen years ago, (whether in the body, I cannot tell; or whether out of the body, I cannot tell: God knoweth;) such an one caught up to the third heaven. And I knew such a man, (whether in the body, or out of the body, I cannot tell: God knoweth;) How that he was caught up into paradise, and heard unspeakable words, which it is not lawful for a man to utter" - 2 Corinthians 12:2-4
Today when a person dies, their soul goes either to heaven or to hell, based on whether the person believed in the Gospel of Jesus Christ or not. If the person was a believer in Christ, who was sealed with the Holy Spirit, then their body goes to the grave, and their soul goes to heaven to be with the Lord. It is for this reason Apostle Paul said:
"(For we walk by faith, not by sight:) We are confident, I say, and willing rather to be absent from the body, and to be present with the Lord" - 2 Corinthians 5:7-8
Apostle Paul knew that since he was a believer in Christ, when he dies, he would be with the Lord, not because of his deeds, but because of Jesus's finished work on the cross. He was so sure of his salvation, because of Jesus, being the perfect sacrifice, Apostle Paul said:
"For to me to live is Christ, and to die is gain" - Philippians 1:21
Apostle Paul was not suicidal when he spoke the above verse, but rather he was sure that he had the gift of eternal life, which is why he described it as such to the Christians in the Church at Phillipi. Apostle John also was sure of his salvation in Christ, and so he too said that people who put their faith in Christ have eternal life:
"These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God" - 1 John 5:13
Moreover, Apostle John, who went ahead and had a glimpse of the future, wrote in the book of Revelation, that there were people in heaven before God's throne, which no man could number. People, who all put their faith in Jesus Christ.
"After this I beheld, and, lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands; And cried with a loud voice, saying, Salvation to our God which sitteth upon the throne, and unto the Lamb" - Revelation 7:9-10
Above all, our Lord Jesus Himself said in John 3:16, that all who believe in Jesus Christ will not perish, but will have eternal life. He also said that the will of God the Father is also the same. Jesus said:
"And this is the Father's will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day. And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day" - John 6:39-40
Jesus, at several places emphasized on "faith in God's Word". He never said that a person would only know whether they will go to heaven or hell after they die. He said the following proclaiming the authority of Jesus, as the Son of God:
"Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life" - John 5:24
The Bible is not a book that contains vague doctrines, but rather it contains clear scriptures that are God breathed. Jesus also said:
"And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand. My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand. I and my Father are one" - John 10:28-30
This is the Good News which the Apostles preached, and for which Jesus Christ died and has redeemed us today. God's Word calls Jesus as the final sacrifice, whose precious Blood takes away the sins of the world. Today, an individual can receive this gift of eternal life, the gift of His Grace by Faith in the Blood of our Lord and Savior Jesus Christ. For this very reason the Bible says:
"For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast" - Ephesians 2:8-9
The Bible also says:
"But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him" - Hebrews 11:6
Under the new covenant of Grace, people are no longer held captive, because we are no longer under the Levitical priesthood, but today we are under the Melchizedek Priesthood of our Lord Jesus who is our High Priest as stated in Hebrews 5:5-10. When a believer in Christ dies, their body sleeps in the grave, waiting for the coming of our Lord Jesus Christ, while their soul goes to be with the Lord in heaven. When Jesus returns, He will first raise all the bodies of those who are asleep, whereas those who are alive, will be raptured to meet the Lord. This is the good news, that all those who believe in Jesus Christ shall not perish, but indeed have eternal life.