Dear FK,As Kosta pointed out recently,this including sin as something planned by God is Manichean heresy that many protestant sects have adapted,especially calvinism.
Our Lord is a Redeemer of those who come to Him sinful and sorrowful with contrite hearts. He is NOT a sin planner for the elect.
Here is a few more From Blessed Saint Aquinas
That there is not any Sovereign Evil, acting as the Principle of All Evils
A sovereign evil should be without participation in any good, as that is the sovereign good which is wholly removed from evil. But there cannot be any evil wholly removed from good, since evil is founded on good (Chap. XI).
2. If anything is sovereignly evil, it must be evil by its very essence, as that is sovereignly good which is good by its essence. But evil has no essence (Chap. VII).
3. That which is a first principle is not caused by anything. But all evil is caused by good (Chap. X). There is therefore no evil first principle.
5. The incidental must be posterior to the ordinary. But evil happens only incidentally and beside the intention (Chap. IV). Therefore it is impossible for evil to be a first principle.
Hereby is excluded the error of the Manicheans.
That Evil is not a Nature or Essence*
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 (B. II, Chap. VI). But God is perfect goodness (B. I, Chap. XLI). 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).
From what you quoted from Blessed Saint Aquinas I don't think you accept the distinction between God USING evil and God CAUSING it. We'll just have to disagree. I understand that the need for men to be sovereign and powerful necessitates the lessening of God. Men have been claiming their sovereign authority (as against) God from the beginning. It is how we were born.
However, of course, that doesn't make it right. :) The reason many cannot accept the sovereignty of God is that it would mean that man was dependent on God, and this just can't be the case for many people. Therefore, they say, if man does not determine his own destiny, and if man is not in control, then God creates evil. It just isn't so. I understand this thinking because I used to think I was the captain of my own ship too.