Cognatio movet Invidiam.

Relationship excites envy. We rarely envy the good fortune of those with whom we are little acquainted; it is those who are nearer to us, in the same school, college, or regiment; or with whom we are intimately related, or associated in the same business, or who are in the same rank in life with ourselves, whose superior success disturbs us. For the success of persons very much superior to us rarely gives rise to this detestable and tormenting passion, which undermines the health, and when in excess occasions melancholy, and even madness. «As a moth gnaws a garment», Saint Chrysostom says, «so doth envy consume a man».

––––«If she but tastes
The slenderest pittance of commended virtue,
She surfeits of it».

In the same spirit Swift says,

«To all my foes, O Fortune send
Thy gifts, but never to a friend
I scarcely can endure the first,
But this with envy makes me burst».