Is there a particular sin, or class of sins, that characterise our times in The West? The most obvious is in relation to sex and sexuality; where moral inversion is most obvious and severe: what was good is now evil; what were sins are now virtues - lauded and rewarded to the skies!
Sex is a powerful human drive; but inversion is a different matter. The modern inversion is a qualitatively different thing from the 1960s style 'sexual liberation' - which was about dismantling restrictions on 'normal' sexuality. Where does inversion come from?
In an ultimate sense, in terms of the spiritual war that is mortal life; it comes from the ascendant power of demons. The primary goal of the powers of purposive evil is opposition to God, to Good, to divine creation. So, inversion is the face of opposition - inversion tells us the major targets of the enemies of God.
So much for ultimates; but that is not how matters impinge-upon the vast majority of modern Western people; who are materialists that deny the reality of the spiritual and divine. The question arises how value-inversion is propagated to the great mass of men - and especially women. Because - on average - women are much more prone to moral inversion specifically, and the maladaptive effects of modernity in general.
And the mediator of moral inversion is The System - which has developed to become a unified thing. In the past, the mass media was smaller and often in opposition to the state bureaucracy and legal system - and state institutions, professions (schools, colleges, medicine etc), trades unions, and corporations were often largely independent and with different and specific goals.
But now all of these groupings have converged, have now become aspects of a single System; are all serving the same agenda; and that agenda is secular, materialist, and Leftist - and this is the primary tool of the demonic side in the spiritual war.
Thus it is The System - in all its various aspects - that imposes value inversion on the mass of people. The System creates a self-consistent, mutually-reinforcing fake world (a virtual-reality or virtuality) which (as the mass media expands, as education expands, as bureaucracy in the workplace expands) encompasses ever more of waking life.
People live mostly in this fake world of The System; and the virtuality is the medium by which inversion is made to seem natural and true.
Therefore, when I ask 'what is the most important sin?', a good answer is to accept the truth and reality of The System -the major sin is to regard The System as Good.
And it follows that the greatest virtue (and one upon which all other virtues depends) is to know The System as evil; to see-through The System to the truth, reality and Goodness beyond; to develop a direct and personal awareness of God and divine creation as different-from, often opposed-to, the public world we so-much inhabit.
Since The System is so large and expanding, since The System is incorporating more and more of the social groupings of The West; this needs to be an individual and personal activity; since The System controls our access-to and interpretation-of so many media - this knowing needs to be direct: Man to Divine, unmediated.
We get to the most important sin and virtue: The current situation is that anyone who believes The System is Good and real, is himself actually in service of the demonic agenda. And only those who recognise The System as evil and fake are able to become Good; are able to join with the meaning and purpose of God's creation and plan.