Gen 2:17, Jn 8:44, 2 Cor 11:3, Isa 14:12-15
God commanded Adam not to eat the fruit of good and evil. God warned Adam that on the day he ate of the forbidden fruit he would surely die. (Genesis 2:17)
Genesis 2:17 But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
The fallen angel Satan deceived Adam into eating the forbidden fruit. (Isa 14:12-15, Gen 3:4-5)
Isa 14:12 How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations! 13 For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north: 14 I will ascend above the heights of the clouds; I will be like the most High. 15 Yet thou shalt be brought down to hell, to the sides of the pit.
Gen 3:4 And the serpent said unto the woman, Ye shall not surely die: 5 For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil.
Satan, the devil, is trying to deceive the unbelievers so that they cannot believe that Jesus is the Christ, and even the believers so that they cannot deeply believe that Jesus is the Christ. (John 8:44, 2 Corinthians 4:4, 2 Corinthians 11:3)
John 8:44 Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.
2 Corinthians 4:4 In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.
2 Corinthians 11:3 But I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so your minds should be corrupted from the simplicity that is in Christ.