The natural always types the spiritual. That is the reason why Jesus used parables in explaining the kingdom of God. In the natural world, something has to die before something can live. Whatsoever any living thing eats, it must die first; be it grain, animal, fish or whatever it is. In other words, some living thing has do die for us to live. That is the law of nature so no one or nothing can escape that. If something has to die before we can live in the natural world, how much more will something not have to die before we can live eternally in the spirit. In much the same way, we must die to self in order to have an eternal life. Water baptism is a symbol of dieing with Christ and resurrecting with Him.
Christianity can be said to be the only true religion because it is the only religion that follows this law of nature.
God always demands a sacrifice. When Adam and Eve disobeyed God, they sewed a fig leaf to cover themeselves but God requires blood so He sacrificed an animal and made coats of skins and clothed them. (Genesis 3:7, 21)
In Cain and Abel's sacrifice, God accepted that of Abel and rejected Cain's. Why? Abel had a revealtion of what God requires (an animal sacrifice) but Cain did not. It is NOT as some preachers say Cain brought rotten fruit unto the Lord. By faith Abel brought God a better offering than Cain did. By faith he was commended as righteous, when God spoke well of his offerings. (Heb 11:4) He had a revelation of what God would do in the future.
This future plan was also revealed through Abraham when God asked him to sacrifice his only son. God showed how He will sacrifice the Lamb of God (Jesus) on the cross. The lamb sacrificed in Egypt saved the Israelites. For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. (John 3:16)
The blood of Jesus shed for our sins is what gives us access to God. Without Jesus' sacrifice, we would be unable to have a relationship with Him. He said, if you do not eat my body and drink my blood, you are not part of me. His body symbolises the Word and His blood represents the Spirit.
Jesus is Lord.
God bless you.