What delusion? What could the author of this definition possibly be referring to? And, if so, would it be a rare thing or something quite common? Now, because this doesn't specifically say what the delusion might be, I admit to being speculative here, but since most of the world is Gentile (as opposed to being Jewish) then perhaps a sermon directed to them might hold a clue or two...
Acts 17:16-34 NASB
(16) Now while Paul was waiting for them at Athens, his spirit was being provoked within him as he was observing the city full of idols.
(17) So he was reasoning in the synagogue with the Jews and the God-fearing Gentiles, and in the market place every day with those who happened to be present.
(18) And also some of the Epicurean and Stoic philosophers were conversing with him. Some were saying, "What would this idle babbler wish to say?" Others, "He seems to be a proclaimer of strange deities,"--because he was preaching Jesus and the resurrection.
(19) And they took him and brought him to the Areopagus, saying, "May we know what this new teaching is which you are proclaiming?
(20) "For you are bringing some strange things to our ears; so we want to know what these things mean."
(21) (Now all the Athenians and the strangers visiting there used to spend their time in nothing other than telling or hearing something new.)
(22) So Paul stood in the midst of the Areopagus and said, "Men of Athens, I observe that you are very religious in all respects.
(23) "For while I was passing through and examining the objects of your worship, I also found an altar with this inscription, 'TO AN UNKNOWN GOD.' Therefore what you worship in ignorance, this I proclaim to you.
(24) "The God who made the world and all things in it, since He is Lord of heaven and earth, does not dwell in temples made with hands;
(25) nor is He served by human hands, as though He needed anything, since He Himself gives to all people life and breath and all things;
(26) and He made from one man every nation of mankind to live on all the face of the earth, having determined their appointed times and the boundaries of their habitation,
(27) that they would seek God, if perhaps they might grope for Him and find Him, though He is not far from each one of us;
(28) for in Him we live and move and exist, as even some of your own poets have said, 'For we also are His children.'
(29) "Being then the children of God, we ought not to think that the Divine Nature is like gold or silver or stone, an image formed by the art and thought of man.
(30) "Therefore having overlooked the times of ignorance, God is now declaring to men that all people everywhere should repent,
(31) because He has fixed a day in which He will judge the world in righteousness through a Man whom He has appointed, having furnished proof to all men by raising Him from the dead."
(32) Now when they heard of the resurrection of the dead, some began to sneer, but others said, "We shall hear you again concerning this."
(33) So Paul went out of their midst.
(34) But some men joined him and believed, among whom also were Dionysius the Areopagite and a woman named Damaris and others with them.
(16) Now while Paul was waiting for them at Athens, his spirit was being provoked within him as he was observing the city full of idols.
(17) So he was reasoning in the synagogue with the Jews and the God-fearing Gentiles, and in the market place every day with those who happened to be present.
(18) And also some of the Epicurean and Stoic philosophers were conversing with him. Some were saying, "What would this idle babbler wish to say?" Others, "He seems to be a proclaimer of strange deities,"--because he was preaching Jesus and the resurrection.
(19) And they took him and brought him to the Areopagus, saying, "May we know what this new teaching is which you are proclaiming?
(20) "For you are bringing some strange things to our ears; so we want to know what these things mean."
(21) (Now all the Athenians and the strangers visiting there used to spend their time in nothing other than telling or hearing something new.)
(22) So Paul stood in the midst of the Areopagus and said, "Men of Athens, I observe that you are very religious in all respects.
(23) "For while I was passing through and examining the objects of your worship, I also found an altar with this inscription, 'TO AN UNKNOWN GOD.' Therefore what you worship in ignorance, this I proclaim to you.
(24) "The God who made the world and all things in it, since He is Lord of heaven and earth, does not dwell in temples made with hands;
(25) nor is He served by human hands, as though He needed anything, since He Himself gives to all people life and breath and all things;
(26) and He made from one man every nation of mankind to live on all the face of the earth, having determined their appointed times and the boundaries of their habitation,
(27) that they would seek God, if perhaps they might grope for Him and find Him, though He is not far from each one of us;
(28) for in Him we live and move and exist, as even some of your own poets have said, 'For we also are His children.'
(29) "Being then the children of God, we ought not to think that the Divine Nature is like gold or silver or stone, an image formed by the art and thought of man.
(30) "Therefore having overlooked the times of ignorance, God is now declaring to men that all people everywhere should repent,
(31) because He has fixed a day in which He will judge the world in righteousness through a Man whom He has appointed, having furnished proof to all men by raising Him from the dead."
(32) Now when they heard of the resurrection of the dead, some began to sneer, but others said, "We shall hear you again concerning this."
(33) So Paul went out of their midst.
(34) But some men joined him and believed, among whom also were Dionysius the Areopagite and a woman named Damaris and others with them.
Humm, this passage makes me wonder still... what could a common delusion be? Well, for openers, there is idolatry. We don't see temples like those in Athens today, but people make their own, don't they? Perhaps not made of stone, but idols of the heart, like work, a spouse or a hobby of some sort. Something that controls everything in their life. Surely, we all have met the person who is all about work, work, work- haven't we? And then there would be those who live their lives devoted to themselves and THEY MAKE THEIR WISHES A god. This sort would never want a creator to intervene with their life, would they? Or how about the religious person, who believes what they do because of the influence of some tradition or authority figure and refuses to submit to the God of the Bible? Then, there are those who simply refuse to believe that Jesus rose from the dead and in spite of this FACT, they still refuse to obey HIM!!! Lastly, there are those who live like there is no tomorrow and would simply say that when we die we are nothing but dust and there is no life after life.
To all these and those with a myriad of other delusions, let me simply say- WAKE UP!!! Jesus did raise from the dead, God will judge us someday and prepare for it by obeying the Gospel of God, today!!! Begin by opening your Bible and allowing truth to permeate your mind and will; the unlimited nature of eternity with God is within your grasp- the rest is up to you!!!!