The devil existing as a separate entity from God is clearly illustrated in book 1 of the old testament and in the description of Christ's temptations during forty days in the wilderness. The Christian bible illustrates that this world has fallen under the power of the evil one, and God has achieved victory over this evil through the suffering and death of Jesus. But evil still exists and in order to be delivered from the power of evil we need to accept Jesus as our Lord and Saviour.
We are currently in the season of Lent, in which we are encouraged to practise self denial in order to strengthen us against the temptations of evil. Humans have been given the freedom to choose, and we often succumb to temptation by doing something which we know to be wrong, yet we still do it.
I agree that there are now many Christians who no longer believe in the devil - and it worries me. It also worries many of my fellow Christians including our local priest. It is the Devil's greatest ploy to convince people that it does not exist.
I mistakenly cited Isaiah 47 in my above post. Apologies. I should have of course cited Isaiah 45. Here is the relevant text for you to contemplate:
"
I am the LORD, and there is none else.
I form the light, and create darkness: I make peace, and create evil: I the LORD do all these things."
Isaiah 45: 6,7
And there you have the classic statement that God is the author of evil as well as good, irrespective of speculations about the Devil.
You might also like to consider a few texts from 2Samuel:
"But the Spirit of the LORD departed from Saul, and
an evil spirit from the LORD troubled him."
1Sam 16:14
similarly
1Sam18:10
1Sam19:9.
Now, as Jeremy has already pointed out, there is no direct reference to the Serpent in the garden of Eden being the Devil - the text simply says that the Serpent proved to be the most subtle beast in the garden. Furthermore, it is quite clear from the text itself that God
lied, and the Serpent told the truth.
In any case, the OT is pretty lean on references to Satan: he appears in the Book of Job, but there he is given completely free reign by God to do as he wills . He is certainly not in open rebellion. The only reference in the OT to Satan having started to act as a totally independent entity is in the book of Zechariah.
As for the New Testament - you cite Christ's temptation in the wilderness. You must know that many Christians interpret this in a metaphorical way as the speculations of a very gifted individual contemplating on just how he might deploy those gifts - to his own personal aggrandisement, or for the benefit of others. In any case, a literal interpretation will simply not cut it. We are told that the "Devil bore him up into a very high mountain and showed him
all the kingdoms of the earth"
. I hardly need point out that even from the top of Everest, the kingdoms of ancient Peru (for example) would be hidden from view, let alone places antipodean to the supposed viewpoint of the two personages.
I don't suppose it's much use recommending a critical study of how the concept of the devil developed in the Bible, nonetheless I will do so (hope springs eternal).
The Devil by Peter Stanford is an extremely readable and informative account by a former Catholic (not sure what he calls himself now, maybe liberal Christian of some sort - anyway, he's a damn good religious critic). Might stop you seeing bogeymen at every turn.