First Question: "This concerns the origin of sin and evil. Since, as we believe, God created everything good, meaning everything created was created in the ontological state of goodness or righteousness, how did Lucifer become evil? Where did the original spark of transgression or rebellion come from? If (as I would answer it myself) it came from Lucifer's free will nature, how is it not also the case that God might also choose against His own nature? This seems to me to be a necessary question arising from our free will doctrine."
Second Question: "Did Adam and Eve know what evil was before they partook of the tree of life? If they were innocent and didn't know anything of evil, how could they stay away from it or make an informed decision to stay away from it?"
To answer these questions we should first consider what is evil? Evil is not a substance. The Fathers tell us that evil does not "exist", per se... which is not to say that evil does not occur, but rather that evil is a choice. It is not something that God created, it is the choice of a will that is in rebellion against God.
St. Basil the Great tell us:
"Again, it is impious to say that evil has its origin from God, because naught [i.e. nothing] contrary is produced by the contrary. Life does not generate death, nor is darkness the beginning of light, nor is disease the maker of heath, but in the changes of conditions there are transitions from one condition to the contrary. In Genesis, however, each being comes forth not from its contrary, but from those of the same type. Accordingly, they say, if it is not uncreated nor created by God, whence does it have its nature? No one who is in this world will deny that evils exist. What, then, do we say? That evil is not a living and animated substance, but a condition of the soul which is opposed to virtue and which springs up in the slothful because of their falling away from good. Do not, therefore, contemplate evil from without; and do not imagine some original nature of wickedness, but let each one recognize himself as the first author of the vice that is in him" (Hexaemeron, Homily 2:4-5, The Fathers of the Church: Saint Basil: Exegetic Homilies, trans. Sister Agnes Clare Way, C.D.P. (Washington, D.C.: Catholic University of America Press, 1963), p 28).St. Diadochus of Photiki says:
"Evil does not exist by nature, nor is any man naturally evil, for God made nothing that was not good. When in the desire of his heart someone conceives and gives form to what in reality has no existence, then what he desires begins to exist. We should therefore turn our attention away from the inclination to evil and concentrate it on the remembrance of God; for good, which exists by nature, is more powerful than our inclination to evil. The one has existence while the other does not, except when we give it existence through our actions" (The Philokalia: The Complete Text, compiled by St. Nikodemos of the Holy Mountain and St. Makarios of Corinth, Vol. 1, trans. G.E.H. Palmer, Philip Sherrard, and Kallistos Ware (London: Faber and Faber, 1979), p. 253).But someone might object, doesn't Scripture tell us that God creates evil? And then they usually will cite Isaiah 45:7, which says in the King James Version: "I form the light, and create darkness: I make peace, and create evil: I the Lord do all these things." What could be more clear than that?
The problem is that we are talking about a translation, and so we need to consider the original word that is translated as "evil" here, (רעה / רע ra‛ / râ‛âh). According to Brown, Drivers, and Briggs, the word can mean:
1) bad, evil (adjective)So how do we know what sense this word has in this particular passage?
1a) bad, disagreeable, malignant
1b) bad, unpleasant, evil (giving pain, unhappiness, misery)
1c) evil, displeasing
1d) bad (of its kind - land, water, etc)
1e) bad (of value)
1f) worse than, worst (comparison)
1g) sad, unhappy
1h) evil (hurtful)
1i) bad, unkind (vicious in disposition)
1j) bad, evil, wicked (ethically)
1j1) in general, of persons, of thoughts
1j2) deeds, actions
2) evil, distress, misery, injury, calamity (noun masculine)
2a) evil, distress, adversity
2b) evil, injury, wrong
2c) evil (ethical)
3) evil, misery, distress, injury (noun feminine)
3a) evil, misery, distress
3b) evil, injury, wrong
3c) evil (ethical)
Hebrew poetry is not based on rhymes, but rather on parallelism. There are different kinds of parallelisms, but this is a classic example of antithetical parallelism. The way antithetical parallelism works is that the first line is followed by a statement that makes an opposing point -- which is not to suggest that the first line contradicts the first, but that it makes a counter point. For example, Psalm 36:9 says:
For evil-doers shall utterly perish, /The first line, which states what the fate of evil-doers will be is contrasted by the second line, which states what the fate of those who wait on the Lord -- and those fates are the opposite of one another.
but they that wait on the Lord, they shall inherit the earth.
In the case of Isaiah 45:7, you have two examples of antithetical parallelism:
I form the light, / and create darkness:So just as darkness is the opposite of light, the "evil" that God creates is the opposite of peace. Given that, the obvious meaning of that word in this context is something like "calamity"... clearly not moral evil. And if you look at more modern translations, you will find that this is how they usually translate it. Furthermore, if you look at what the Fathers say about this passage, they also understand it in this sense.
I make peace, / and create evil
So to answer the first question, Satan was not created evil. He was created good, but made the choice to rebel against God, and to do evil.
And while created beings can rebel against God, God cannot rebel against Himself. God is infinite and perfect. Scripture tells us that He is Love, Truth, Light, Good, and that it is impossible for him to lie or to sin, and so it is not possible that He could choose evil.
To answer the second question, Adam and Eve had not known evil, but they did have the power of choice, they knew what God required of them, and they knew the consequences that would follow if they did not obey God. Their knowledge was limited, but the expectations that God placed on them were also very limited, and so they had the power to choose, and it was just for God to hold them accountable for that choice.
For more information:
The God who is Silent about Evil, by Fr. Georges Massouh
The Nature and Origin of Evil According to Eastern Christian Church, by Marina Luptakova
Does God create evil? (Christian Apologetics & Research Ministry)