For nothing is more blamefull to a Knight,
That court’sie doth as well as armes professe,
However strong and fortunate in fight,
Then the reproch of pride and cruelnesse:
In vain he seeketh others to suppresse,
Who hath not learned himself first to subdue:
All flesh is frayle and full of ficklenesse,
Subject to fortunes chance, still chaunging new;
What haps to-day to me to-morrow may to you.

Edmund Spenser (c. 1552-1599) English poet

The Faerie Queene, Book 6, canto 1, st. 41 (1590-96)
    (Source)