I remember being in numerous churches where the pastor would turn to the Book of Judges and use Gideon as an example of someone who was faithful because he wanted to make sure of the will of God in order to do it. We were then told to put out our fleeces to figure out the will of God for ourselves as well. I find it amazing that we were never told to use other figures in Judges as examples to mimic. For instance, why not tell us to sacrifice our children or be captured by our enemies so we can take them down? Why not tell us to slaughter our siblings to secure our inheritance? Why? Because the judges in the Book of Judges are doing things that are wrong. That's the whole point. We weren't meant to mimic them, but to shake our heads and NOT do the same; but rather use our faith to know the will of God through what He has revealed. Hence, in Deuteronomy 18:10-13, we are told that God detests anyone who interprets omens.
An omen was a sign to which someone looked to interpret an event, present, past or future. It was seeking to know God's will through an alternate means of interpreting events. Our modern omens are the ideas we have gained through our lives that function as interpretive guides to our experiences. In fact, we just mesh them all together and call them "experience," when we really mean what we have learned by applying external grids of ideas to our experience. In any case, trying to read experience through alternate means other than the Word of God is really what the prohibition against omens is all about.
This is really important to understand. You see, according to Deuteronomy 32:7-14, Israel alone was set apart as God's people. The rest of the nations were given over to the rule of demons who then create their own religions through which men might pay homage to them (v. 17; see also Rev 9:20). In the New Testament, we see the same thing. The people of God's family are extended through Christ to all who believe. It is over them that He rules; but the rest of the world remains as that which was given over to the devil as his domain. He is called the ruler of this world (John 14:30), the god of this world (2 Cor 4:3-4), and the prince of the power of the air (Eph 2:1-3), which refers to both his invisible presence and influence in the world. Consider Paul's words in First Corinthians 10:20:
[No,] but [I say] that the things which the Gentiles [i.e., those who do not believe and belong to the world] sacrifice, they sacrifice to demons, and not to God; and I do not want you to become sharers in demons.
Notice here that the world, then, is ruled by the demonic; but why is this important for us to know? Because this is why omens, i.e., trying to figure out God's will by reading what goes on in the world, what goes on in our lives, etc. with the worldview given to us by the god of this world, are bad and will lead us to what is false. If we attempt to read our experience, we are attempting to know the will of God, i.e., what is right and wrong, true and false, through this world's system, which is based on the influence of our adversary. How do you think that's going to work out for you?
Hence, we are told that the spirit of the age is one that leads to a life without God in Ephesians 2:1-3, 11-12
And you were dead in your trespasses and sins, in which you formerly walked according to the course of this world, according to the prince of the power of the air, of the spirit that is now working in the sons of disobedience. Among them we too all formerly lived in the desires of a this-worldly life, indulging the desires of a this-worldly life and of a this-worldly mind, and were by nature children of wrath, even as the rest . . . Therefore remember that formerly you, the Gentiles in the flesh, who are called "Uncircumcision" by the so-called "Circumcision," [which is] performed in the flesh by human hands --[remember] that you were at that time separate from Christ, excluded from the commonwealth of Israel, and strangers to the covenants of promise, having no hope and without God in the world.
Notice that we were without God in the world as unbelievers because we were excluded from the covenants of promise and had not hope. We did not know God's will because we did not know God through other religions and/or through our personal experience. We did not, because we could not. This world belongs to the devil. The spirit of the age, i.e., the way that we think, the way that our culture thinks, the way that our religious culture thinks, if it is not saturated with what is transcendent revelation from God, is what we have to interpret this world's experiences with. Because of this, apart from the Word of God, we will always misconstrue events in our lives and misinterpret them with a demonically inspired worldview. In other words, there is no neutrality. If we do not use what has been given to us in God's Word to understand the world, the spirit of the age that is produced by the ruler of this world will automatically be our default position and we will interpret all things accordingly.
This is precisely why God commanded His people to not seek out His will through omens, but through what He had given them. Hence, in Deuteronomy 29:29, we are told:
"The secret things belong to the Lord our God, but the things revealed belong to us and to our sons forever, that we may observe all the words of this law."
This is the only way to escape the redrawn shades of meaning the devil's light provides for us to interpret our experience in the world. Otherwise, if we seek out to understand on our own, he already has us, as he has been training us through our culture, and through fanning our disbelieving nature, since birth. We will misread this world because it is his world to be misread. Whatever we need in our lives to complete that deception, he is more than willing to provide it. He desires our sorrow and damnation, as "wretches find comfort in the fellow sufferings of others."
But God who rules His people has called them out, not through the spirit of this age, but by His Holy (distinct and set apart) Spirit by giving us the word of His gospel and the Word of God that this gospel message calls us toward. He seeks the renewing of our minds that our continually reinfected with the interpretations of life the devil wants to give them. He seeks to wash us with the Word, and to give the Word to others that they too may be washed from the demonic filth of this world's thinking.
Let me put this in application to myself. If I were to try to read my experience as an indication of God's favor upon me, I would conclude that He has no favor upon my life. I have lost jobs, health, finances, many of my possessions, friends, my dad, and now my mother's life is threatened. Prayers have not been answered in many of these things. Should I be given over to attempting to read God's will for my life through these things, I would surely conclude that either God has forsaken me, God never knew me, or that He does not exist in the first place.
Now, I have a choice to make. I can interpret my experiences through the spirit of this age, or I can throw myself into the Word of God and let the Spirit of God interpret my experiences through it. If I choose the former, it will either lead to my rejection of the Bible as the Word of God, as it tells me something quite different than what I have come to believe as true through the spirit of the age, or it will lead to my rejection of the idea that God exists. Either way, I will make some sort of move to undermine the Scripture and the truth due to my alternate means of interpreting all things. And that's exactly what the devil wants of all of this. It's his world, so all roads lead to unbelief therein.
But if I trust in God's Word, then I have an interpretation of life that runs counter the spirit of the age. The things in my life have not necessarily occurred because of God's nonexistence or disfavor, but precisely because of His favor. I am told that every child of God is disciplined in order that he might become a partaker in God's holiness, see God, and bear more fruit. I am told that this pattern is normative for every Christian, not just the really bad ones that God doesn't like (as if there are any of that sort). In other words, as long as I am following Christ in a life of repentance and faith, I can trust the promises given in the Word of God that God is saving me and those around me through suffering and tragedy. It is not to give me a better life here. It is to work toward the holiness of both myself and His people. But you're not going to get that from reading your experience with the spirit of the age. Only false beliefs reside within that worldview. It will take you away from the will of God, not toward it, and it will inevitably lead to darkness and despair in the world to come when the spirit of this age falls apart with the passing world to which it was a part.
Hence, reading omens in Scripture is said to be an evil thing. It distrusts God's ability to communicate sufficiently to His people, and it takes us away from the truth of God's salvation. It calls us to the winds and waves of this world, and will bring us to despair; but God calls us to His Word, to faith, hope, and love in and of His revealed will. It is the lifeline in a sea of trouble, the light that shines in a very, very dark place (much darker than we imagine it to be, as the spirit of this age convinces us of its bright future).
If I interpret the will of God by the way I feel, by the events that take place within the day, by the tragedies that occur, by even the claiming of my own life, I will be brought to think that God favors me when things are going well and disfavors me when things go awry; but this is the stupidity of false religion, as though God is so fickle to constantly change His mind day to day. We cannot let experience be our guide, because we cannot let the devil and our disbelieving nature be our guide. We must put our hope and trust in what God has spoken, as our experiences will come and go, but what He has declared stands both now and forever. Revelation is all we've got, and to ignore it, diminish it's authority, or even put it on par with our experience is to give the devil a great foothold on your life, and once he has that, the door of your life is much easier to open, so that he can come in and rule you as he does the rest of the world. But God has shown us mercy by creating and preserving this Word for us that he might not overcome us. It carries the message of our salvation, our adoption, our hope in a dying world. It is where we must go to interpret the significance of all things, especially the will of God. Ask, "Why?" but ask it of Scripture, not into the air or in attempting to make sense of things by yourself, for left on your own, the devil has you; but God has set down this beacon of light for you that you might not be his captive anymore.
If you are a Christian, stop interpreting your experience with the spirit of this age, with your culture, with your religious traditions, with what mom and dad or your teachers taught you, and put your faith in the Scripture that is a lamp unto your feet and a light unto your path. If you are not a Christian, come away from the darkness of being without God in the world, interpreting all experiences through a continually moving grid of faddish philosophies and man-made ideals, and believe on the Lord Jesus Christ and be saved from this wicked generation.
Without the Word of God, we don't have God's influence in our thoughts. We have only the devil's; but the good news is that we can come to Christ, and through Him can be restored to God that we might claim all of the promises of our salvation, promises revealed within the His Word, and begin to be washed and renewed in our minds by the power therein. And that alone will save us in the day when this life falls apart and the spirit of this age can no longer fill our heads with false hopes. Instead, we say to Christ, as His disciples have always said, Where else shall we go? You have words of eternal life (John 6:68).
Heaven and earth shall pass away, but My words shall never pass away. (Matt 24:35)
The grass withers, the flower fades, but the word of our God stands forever. (Isa 40:8)