Found it!
It's a bit long. But that isn't really new for me...
"the devilish strategy of pride is that it attacks us, not on our weak points, but on our strong. It is preeminently the sin of the noble mind - that
corruptio optimi that works more evil in the world than all the deliberate vices. Because we do not recognize pride when we see it, we stand aghast to see the havoc wrought by the triumphs of human idealism. We meant so well, we thought we were succeeding - and look what has come of our efforts! There is a proverb that says that
the way to hell is paved with good intentions. We usually take it as referring to intentions that have been weakly abandoned, but it has a deeper and much subtler meaning. That road is paved with good intentions strongly and obstinately pursued until they have become self-sufficing ends in themselves and deified.
Sin grows with doing good...
Servant of God has chance of greater sin
And sorrow, than the man who serves a king.
For those who serve the greater cause may make the cause serve them,
Still doing right."
Also,
"Human happiness is a by-product, thrown off in our service of God"
Both quotes are from Dorothy L. Sayers "The Other Six Deadly Sins." The poem that she quotes is from T. S. Eliot's
Murder in the Cathedral.
Corruptio optimi is a Latin phrase meaning 'a corruption of what is best.' It is from a slightly longer phrase -
corruptio optimi pessima - which means 'a corruption of what is best is worst.'
Emphasis on the proverb is my own.
I think Jack talked about this too (they knew each other, incidentally), but I can't remember where. If I remember the point though, it was that pursuing the will of God is a good far greater than curing social ills; but if that will is pursued, we'll find the social stuff taken care of on the way.
"Seek ye first the Kingdom of God and His righteousness, and all these things shall be added" and such.