St Paul realized that his being a brilliant orator, high-adept, and genius were ultimately irrelevant to salvation
Indeed, for most people, now and in the past; this is almost a definition of "religion" - redirecting our will, training and implementing our will.
And when people are not getting better; the answer is therefore intensification of willed-effort across a longer span of time.
I personally underwent, in accordance with my will, two prolonged and intensive efforts at self-transformation in search of new abilities: first in medicine, secondly as a scientist.
The years-long and immersive training as a doctor had many effects on me; and I developed many abilities. But there were costs. My personality was somewhat distorted and considerably hardened; and I became prone to be negatively-motivated by the group ethos, especially by a nagging sense of guilt - that lasted several years, even after I ceased to practise as a doctor.
The years of training as a scientist also developed new aptitudes and habits, especially in the realms of thinking. I became not just able, but also almost compelled, to adopt explicit and few assumptions; stick-to and follow-through clear and transparent lines of reasoning from them; and to exclude all other factors that were not part of the "model".
This was a deep change, and it made me a pretty good scientist; but was bad for me as a person, overall - at least until it was understood and contained. Because it was a deliberate but also compulsive form of self-blinding.
In sum; the application of will in a prolonged and intensive training led, in both medicine and science, to functionality and power in a this-worldly sense; but were spiritual dead-ends that impaired me in significant ways as a person.
I believe that exactly the same applies within the realms of spirituality and religion.
I mean that when people pursue their religion by prolonged and intense training, by exercise of will (for example in the training and initiation of a priest or monk, or the leading of a rigorous, devout, or holy life) - the result can certainly be enhancements of of the mind in accordance with will; a transformation of personality; an increase of ability, of power...
But the outcome of any sustained and focused exercise of our conscious will, is also a degree of spiritually-negative distortion of our nature.
We may delude ourselves otherwise; but this becomes obvious if we can spiritually evaluate other people, and how observe the ways they are changed by prolonged and intensive effort in accordance with their conscious will-power.
This was an insight of St Paul; who recognized that he himself had been impaired by the effects of his prolonged and intensive (and high-level) initiation into Priesthood.
Paul realized - indeed he knew, from experience - that Men could not be improved in their spiritual quality by an exercise of will...
That no matter how much we wanted and strove to become better, and now matter how genuine was this desire and effort; we are unable to accomplish this.
For Paul; this was a great insight into the nature of reality, the nature of what Jesus needed to do to help us (help genuinely and qualitatively) - and also a revelation of what Jesus actually did:
With Jesus there was not (ultimately false) promises of positive personal transformation and enhancement; achievable by following his new prescription of attitude and activities; and rewarded by salvation...
What Jesus offered was not a new (and better!) sort of life and mind therapy - not even a spiritual therapy; but something altogether different.
I think Paul saw vividly the limitations of human will and effort; probably because he had himself first accomplished so much by his own will and effort, but then recognized (in a flash) that all this was irrelevant to what Jesus had done for us.
But this truth is a slippery insight: hard to keep a-hold-of (indeed, Paul often drifted from it), such are the advantages of the kind of worldly enhancements and satisfactions we may achieve from applying our will-power in a sustained and focused way.
In sum: Training and initiation may certainly be useful in this life and world; but such achievements do not and cannot make us better people, or better followers of Jesus - and, indeed, most often our transformation and enhanced aptitude will function as a snare, a distortion, and a distraction.
