The Forbidden Fruit is the Sins the Satan
The whole humanity dies for the wages of sin (Romans 6:23) like Adam and Eve died owing to the Forbidden Fruit.
As the Bible has it, everyone dies for his sin (Jeremiah 31:30). And sin, when it reaches maturity, produces death (James 1:15). And the death entered the world through sin, and so passed on to all persons in that all sinned (Romans 5:12).
Therefore the Forbidden Fruit and Sin are the same things.
On the one hand, Satan is the agent who wields the power of death (Hebrews 2:14), and sin is a king in the mortal body (Romans 6:12), who reigns in death (Romans 5:21). Therefore Satan is Sin, and Sin is Satan.
On the other hand, Satan is the Evil Spirit, and the Evil Spirit is the Evil Heart, and the Evil Heart is the Forbidden Fruit. Accordingly, Satan is just the Forbidden Fruit. We can demonstrate this truth in other words also.
God initially knew the good only
The writer of Genesis said that God made the tree of the knowledge of good and evil. (Genesis 2:9). But it was not the case. If God had made the Forbidden Fruit, he would know that Adam and Eve would eat it, for he was omniscient and omnipotent. With all his knowing that Adam and Eve would eat it, if he had made it on purpose, he must have been Satan who would destroy the Eden. But God is love and good (Mark 10:18).
Therefore God must not have made the Forbidden Fruit. Now, to tell the truth, the Forbidden Fruit was the spirit of Satan who was God’s enemy from the beginning.
Therefore, Adam and Eve did not eat a physical fruit but were consumed by a spiritual fruit; that is Satan. So the Bible expresses being given the spirit as drinking the spirit (1 Cor 12:13).
Meanwhile, the Bible says that the serpent tempted Eve to eat the forbidden fruit. The snake symbolises Satan (Genesis 3:1, Revelation 20:2), and the Forbidden Fruit symbolises Satan’s heart. But Satan and Satan’s heart are the same things, because Satan is the Evil Spirit, and Satan’s heart is the Evil Spirit also. Therefore, the Forbidden Fruit is Satan, and Satan is just the Forbidden Fruit.
As we have seen so far, the Forbidden Fruit is Sin, and Sin is Satan, and Satan is the Forbidden Fruit.