Harley,it does not seem you read the whole thing- the first cause which is always God is good and evil is not a nature or essence so evil is always an accident that is caused by the will against the first cause. This does not mean that someone does not know they are willfully sinning either.Sometimes we sin out of ignorance and sometimes we sin knowingly
More Aquinas backed up with Scripture....
Evil is nothing else than a privation of that which a thing is naturally apt to have and ought to have. But a privation is not an essence, but a negation in a substance.
5. Every essence is natural to some thing. If the essence ranks as a substance, it is the very nature of the thing. If it ranks as an accident, it must be caused by the principles of some substance, and thus will be natural to that substance, though perhaps not natural to some other substance. But what is in itself evil cannot be natural to anything: for the essence of evil is privation of that which is naturally apt to be in a thing and is due to it. Evil then, being a privation of what is natural, cannot be natural to anything. Hence whatever is naturally in a thing is good, and the want of it an evil. No essence then is in itself evil.*
6. Whatever has any essence is either itself a form or has a form,* for by form everything is assorted in some genus or species. But form, as such, has a character of goodness, being the principle of action and the end which every maker intends, and the actuality whereby every subject of form is perfected. Whatever therefore has any essence, as such, is good.
7. Being is divided into actuality and potentiality. Actuality, as such, is good, because everything is perfected by that whereby it actually is. Potentiality too is something good: for potentiality tends to actuality, and is proportionate to actuality, not contrary to it; and is of the same genus with actuality; and privation does not attach to it except accidentally.* Everything therefore that is, in whatsoever way it is, in so far as it is a being, is good.
8. All being, howsoever it be, is from God. But God is perfect goodness . Since then evil cannot be the effect of goodness, it is impossible for any being, as being, to be evil.*
Hence it is said: God saw all things that he had made, and they were very good (Gen. i, 31): He made all things good in his own time (Eccles. iii, 11): Every creature of God is good (1 Tim. iv, 4).
I realize that God created everything good. But Christ calls us evil.
Mat 7:11 If you then, who are 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!
This is the fall of man. It is impossible for us to be totally obedient to God simply because we don't wish to be. And without total obedient to all that is good and perfect it is impossible to please God because God is all that is good and perfect. Our only salvation is in the one who was totally good and perfect-our Lord Jesus.
I might add that it is rather interesting that Adam in the garden was happy and content to do the Lord's work. God asked him to name the animals and so he did. God put him to work in the garden and he was happy to do it. And the work must have been strenuous because God decided Adam needed a helper. But when God gave Adam one command of what NOT to do, Adam could not resist but to do the very thing God did not want done. It simply exposed Adam's weakness for disobedience to God.
Adam wasn't flawed and God didn't trap Adam. Nor was judgment of Adam a change in Adam's nature. God simply showed Adam and his race that he has a disposition not to do good. And if you can't do good all the time, then you are evil in God's eyes. Our only hope is in the salvation of Christ.