Evil cannot be a first cause of God because God wills everything good,dear brother.
Evil is a defect from perfection,thus if God willed evil to exist it would part of God's essence and first cause,thus God would have evil in Him and therefore would not be perfect.
Evil can only enter the world by God giving us a free will
That God cannot will Evil By Saint Thomas Aquinas
EVERY act of God is an act of virtue, since His virtue is His essence (Chap. XCII).
2. The will cannot will evil except by some error coming to be in the reason, at least in the matter of the particular choice there and then made. For as the object of the will is good, apprehended as such, the will cannot tend to evil unless evil be somehow proposed to it as good; and that cannot be without error.* But in the divine cognition there can be no error . 3. God is the sovereign good, admitting no intermixture of evil . 4. Evil cannot befall the will except by its being turned away from its end. But the divine will cannot be turned away from its end, being unable to will except by willing itself . It cannot therefore will evil; and thus free will in it is naturally established in good. This is the meaning of the texts: God is faithful and without iniquity (Deut. xxxii, 4); Thine eyes are clean, O Lord, and thou canst not look upon iniquity (Habi, 13).
Think about that for a minute. How could Satan who was created as a perfect creature have a defect? Or Adam? Just by the very definition, he would not be a perfect creature.
James tells us the reason man falls away. We simply lust after the things of this world. And lusting brings forth sin, and sin death. It isn't "free will" that we make a choice to sin or not. Rather we simply lust for something to such a point that we have to sin.
It's like looking at that big screen TV at Best Buy until we just have to have it.