The Bible doesn't say that either.
In a often overlooked passage God uses the King of Tyre as an example to describe how Satan was actually created as a protector in the Garden. It was Satan who took opportunity (via pride) to disobey God and therefore fell (we learn in Revelation that about one third of the angels fell with him).
Ezekiel 28:11 Moreover the word of the LORD came to me, saying, 12 “Son of man, take up a lamentation for the king of Tyre, and say to him, ‘Thus says the Lord GOD: “You were the seal of perfection, Full of wisdom and perfect in beauty. 13 You were in Eden, the garden of God; Every precious stone was your covering: The sardius, topaz, and diamond, Beryl, onyx, and jasper, Sapphire, turquoise, and emerald with gold. The workmanship of your timbrels and pipes Was prepared for you on the day you were created. 14 “You were the anointed cherub who covers; I established you; You were on the holy mountain of God; You walked back and forth in the midst of fiery stones. 15 You were perfect in your ways from the day you were created, Till iniquity was found in you. 16 “By the abundance of your trading You became filled with violence within, And you sinned; Therefore I cast you as a profane thing Out of the mountain of God; And I destroyed you, O covering cherub, From the midst of the fiery stones. 17 “Your heart was lifted up because of your beauty; You corrupted your wisdom for the sake of your splendor; I cast you to the ground, I laid you before kings, That they might gaze at you. 18 “You defiled your sanctuaries By the multitude of your iniquities, By the iniquity of your trading; Therefore I brought fire from your midst; It devoured you, And I turned you to ashes upon the earth In the sight of all who saw you.
Therefore we know that Satan was created as a "anointed cherub who covers" and it was Satan who fell (God didn't create him evil) "You corrupted your wisdom for the sake of your splendor".
The case is now closed! There could never be a more clear description of how Satan was actually created as a protector who fell and turned evil.
MORE EVIDENCE:
To drive home the point even further, we also know that after creation God said everything was "good" (at this point Satan was still good).
Genesis 1:31 Then God saw everything that He had made, and indeed it was very good. So the evening and the morning were the sixth day. 2:1 Thus the heavens and the earth, and all the host of them, were finished.
At creation everything in heaven and on earth were good! (even Satan).
Yet Satan fell by tempting Eve to sin.... notice what God tells Lucifer regarding what Lucifer did in the garden...
Genesis 3:14 So the LORD God said to the serpent: “Because you have done this, You are cursed more than all cattle, And more than every beast of the field; On your belly you shall go, And you shall eat dust All the days of your life.
“Because you have done this, You are cursed"
“Because you have done this"
God cursed Satan because what he did in the garden, God did not create Satan as a evil being.
Furthermore...
Would a perfect father put a poisonous snake in the crib with his new born baby?
Of course not! God put Satan in the garden as a protector! Yet Satan fell. Satan used his own freewill to disobey God and thus the history of mankind begins with a bang!
God sums it up like this....
Matthew 7:9 “Or what man is there among you who, if his son asks for bread, will give him a stone? 10 “Or if he asks for a fish, will he give him a serpent? 11 “If you then, being evil, know how to give good gifts to your children, how much more will your Father who is in heaven give good things to those who ask Him!
