Concerning the origin of moral evil, Abraham Booth writes: 
"Were my opinion asked respecting the origin of moral evil,
 the answer would be, I have no opinion upon the subject: nor dare I 
form conjectures about it. Having long been fully persuaded, that a 
satisfactory solution of the question lies far beyond the reach of human
 intellect; I consider it as more becoming my feeble reason, and much 
more respectful to Divine Providence, to exclaim with Paul, O the depth!
 than to indulge in speculation on a subject so mysterious; lest I 
should fall under the righteous reproof of Jehovah's interrogatory to 
Job, who is this that darkens counsel by words without knowledge?" (Abraham Booth, Works, Volume 3 from Google Books).
Oh, but you do have an opinion on the subject Mr. Booth! And you proceed hypocritically to "form conjectures about it" by asserting "that a satisfactory solution of the question lies far beyond the reach of human intellect." O the depravity of those like Booth who darken counsel by pseudo-pious platitudes to conceal their ultimate rebellion against 
Jehovah and His Anointed. O the blindness of those like Booth who indulge in vain speculation on a subject so straightforward and clear.
The salvation that is found exclusively in Jesus Christ is according 
to God’s eternal purpose (Ephesians 3:11). There are indeed inscrutable mysteries and unfathomable depths (Romans 11:33; cf. Ephesians 3:11-21) concerning God's eternal purpose to glorify Himself in the cross-work of Christ, and in the hearts of His people. But the origin of moral evil is not one of those mysteries since, again, God's eternal purpose was to demonstrate His glory (see Romans 9:18-24).
God made the fall of Adam (and in him his 
posterity) an inevitable certainty by ordaining and causing it to 
happen. Many similarly-minded with Booth speak of the fall of Adam and especially the fall of Satan as the “greatest mystery”
 in all of Scripture. To them, the most profound and perplexing mystery 
is the origin of moral evil in created beings. To those who submit to the clear
 testimony of Scripture, it is NOT a mystery at all. God ordained before
 eternal times to elect and save His people and to actively cause the 
fall so that He might be glorified in the Person and Work of His Son.
“ ... according to the eternal purpose which He accomplished in Christ Jesus our Lord” (Ephesians 3:11). 
“Then do not be ashamed of the testimony of our Lord, nor of me, His 
prisoner. But suffer hardship with the gospel, according to the power of
 God, the One having saved us and having called us with a holy calling, 
not according to our works, but according to His own purpose and grace 
given to us in Christ Jesus before eternal times, but now revealed 
through the appearance of our Savior, Jesus Christ, indeed making death 
of no effect, bringing life and incorruptibility to light through the 
gospel, for which I was appointed a herald and apostle and a teacher of 
nations” (2 Timothy 1:8-11). 
  
“So, then, to whom He desires, He shows mercy. And to whom He 
desires, He hardens. You will then say to me, Why does He yet find 
fault? For who has resisted His will? Yes, rather, O man, who are you 
answering against God? Shall the thing formed say to the One forming it,
 Why did You make me like this? Or does not the potter have authority 
over the clay, out of the one lump to make one vessel to honor, and one 
to dishonor? But if God, desiring to demonstrate His wrath, and to make 
His power known, endured in much long-suffering vessels of wrath having 
been fitted out for destruction, and that He make known the riches of 
His glory on vessels of mercy which He before prepared for glory, whom 
He also called, not only us, of Jews, but also out of nations” (Romans 
9:18-24).
