"a" sharp tongue vs. "the" pointing finger

Solution 1:

‘A sharp tongue’ is merely a metaphor. It should be readily understood in and of itself, despite its impossibility. Even in the passage quoted, wouldn’t ‘a’ suit the metre better?

’The pointing finger’ seems proverbial and suggests an archetype; a one-of-a-kind meme, trope or cultural icon symbolic of an eternal truth and yes, a Platonic ideal.

Anciently Isaiah (58:9-12) invokes ‘If you take away the yoke from your midst, THE POINTING OF THE FINGER, and speaking wickedness… then you will call and the Lord will answer…’ in which a third article would surely describe ‘the speaking of wickedness…’

Clearly John the Baptist used ‘a’ and not ‘the’ finger to point Jesus out but only weeks ago, Pope Francis re-told that story choosing exclusively ‘the’ over ‘a’ for 11 nouns or adjectives that not only could have been indefinite, but would have made his point more clearly if they had been… as with ‘…the preacher of repentance and baptizer who points to the true baptizer in the Holy Spirit”. Of course ‘the true baptizer in the Holy Spirit’ merits definite articles but the distinction would be the greater if John were merely ‘a preacher’ or ‘a baptizer’

The Pope sees that as so important that ‘The vocation of all Christians is “to be witnesses to Jesus”, to fill their lives with the“gestures” typical of John the Baptist: “pointing to Jesus”.’

Glossing over the words on Belshazzar’s wall because that finger was writing, not pointing, Omar Khayyám also used ‘the’ not ‘a’ for his Moving finger, Agatha Christie kept that ‘the’ when she swiped the line for a book title.

Getting back to pointing, 1919-32 saw at least three films entitled ‘Pointing Finger’ films use ‘The.’

Is all this just pretentiousness, at which the finger of scorn should be pointed?

Solution 2:

To have a sharp tongue is a common idiom in English, meaning something like "to habitually utter harsh or mean things with no warning". *To have a pointing finger, on the other hand, is not, though we could possibly guess what such an idiom would mean (something like "to habitually point out errors or blame others").

That being said, I don't believe this particular case is a matter of native speakers intuitively understanding how to deploy "a" and "the". The usage of "the" in "the pointing finger" is odd, and reads as literary to me.

If the sentence said "a pointing finger", it might be in danger of being taken too literally, that personified arrogance is actually pointing something or someone out. Instead, "the pointing finger" to me sounds more like it is invoking almost a Platonic ideal of the act of blaming: this personification of arrogance has "the" kind of finger that someone who is always blaming others and calling out errors would have; it is a finger that is quick to point out such errors and sinners. But it is not "a pointing finger" - that would be a finger that is always extended and always pointing at something, whether its owner means it to or not.

(I don't want to be taken too literally in this answer either - I'm just trying to transcribe my own psychology of reading this sentence and trying to describe the mechanics of what that weird "the" is doing in the sentence.)

So, basically, this seems to be an instance of deliberately breaking the rules of usage to invoke a unique, figurative sense.