The Cur, the Horse, and the Shepherd’s Dog

Moral: No Moral. Suggest us a moral of this fable in comment section.
The lad of mediocre spirit
Blurs not with modesty his merit.
On all exerting wit and tongue,
His rattling jokes, at random flung,
Bespatter widely friend and foe.
Too late the forward boy will know
That jokes are often paid in kind,
Or rankle longer in the mind.
A village cur, with treble throat,
Thought he owned music’s purest note,
And on the highway lay, to show it
Or to philosopher or poet.
Soon as a roadster’s trot was heard,
He rose, with nose and ears upreared;
As he passed by assailed his heels,
Nor left him till they reached the fields.
But, as it happened once, a pad,
Assailed by Master Snarl, like mad,
Flung out, and knocked him in the mire;
Nor did he stop to care, inquire,
If he had hurt him. On his way
Pad passed, and puppy bleeding lay.
A shepherd’s dog, who saw him bleed,
Who hated Snarl and all his breed,
Said, “This was brought about by prate,
Which horses—even horses—hate!”