Where in the Bible did God tell Adam and Eve that they have sinned? I was wondering where in the Bible I can find that God told Adam and Eve that they have sinned after they have eaten the forbidden fruit from the tree.
Sin is described in the Bible as transgression of the law of God (1 John 3:4) and rebellion against God (Deuteronomy 9:7; Joshua 1:18).  After creating Adam, God issued only one prohibition in His instructions: 


  “The Lord God took the man and put him in the Garden of Eden to work it and keep it.  And the Lord God commanded the man, saying, “You may surely eat of every tree of the garden,  but of the tree of the knowledge of good and evil you shall not eat, for in the day that you eat of it you shall surely die” (Genesis 2:15-17).


It was only after Adam and Eve disobeyed God’s command, after they had eaten of the fruit of the tree of the knowledge of good and evil that “their eyes were opened” – and they tried to hide from God:


  “But the Lord God called to the man and said to him, “Where are you?” And he said, “I heard the sound of you in the garden, and I was afraid, because I was naked, and I hid myself.”  He said, “Who told you that you were naked? Have you eaten of the tree of which I commanded you not to eat?”  The man said, “The woman whom you gave to be with me, she gave me fruit of the tree, and I ate.”  Then the Lord God said to the woman, “What is this that you have done?” The woman said, “The serpent deceived me, and I ate” (Genesis 3:7-13).


God does not use the word “sin” when he pronounces judgment on Adam and Eve for their disobedience.  But God does say WHY they have sinned against Him.  God says to Adam:


  “Because you have listened to the voice of your wife and have eaten of the tree of which I commanded you, ‘You shall not eat of it,’ cursed is the ground because of you; in pain you shall eat of it all the days of your life; thorns and thistles it shall bring forth for you; and you shall eat the plants of the field. By the sweat of your face you shall eat bread, till you return to the ground, for out of it you were taken; for you are dust, and to dust you shall return” (Genesis 3:17-19).


Adam and Eve succumbed to the temptation “to be like God, knowing good and evil” (Genesis 3:4).  They disobeyed God – and they knew they had done wrong.  That is the original sin that “came into the world through one man” – Adam – and a direct consequence of that sin is death:


  “Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned—  for sin indeed was in the world before the law was given, but sin is not counted where there is no law.  Yet death reigned from Adam to Moses, even over those whose sinning was not like the transgression of Adam, who was a type of the one who was to come” (Romans 5:12-14).


Through Adam sin entered the world, and so death was passed on to all men because “the wages of sin is death” (Romans 6:23).  That is what the Bible has to say about sin and how it originated.  Adam and Eve disobeyed God because they wanted “to be like God, knowing good and evil.”  That is sin.