“It has been related that dogs drink at the river Nile running along, that they may not be seized by the crocodiles.”
Book I, fable 25, line 3.
Fables
Help us to complete the source, original and additional information
Phaedrus 16
Latin fabulist and probably a Thracian slave -20Related quotes

“To eat the lotus of the Nile
And drink the poppies of Cathay.”
The Tent on the Beach, reported in Bartlett's Familiar Quotations, 10th ed. (1919)

“619. You may bring a horse to the river, but he will drinke when and what he pleaseth.”
Jacula Prudentum (1651)

The Decline and Fall of Practically Everybody (1950), Part I: It Seems There Were Two Egyptians, Cheops, or Khufu

1860s, Allow the humblest man an equal chance (1860)
Context: So that saying, "in the struggle between the negro and the crocodile," &c., is made up from the idea that down where the crocodile inhabits a white man can't labor; it must be nothing else but crocodile or negro; if the negro does not the crocodile must possess the earth; [Laughter; ] in that case he declares for the negro. The meaning of the whole is just this: As a white man is to a negro so is a negro to a crocodile; and as the negro may rightfully treat the crocodile, so may the white man rightfully treat the negro. This very dear phrase coined by its author, and so dear that he deliberately repeats it in many speeches, has a tendency to still further brutalize the negro, and to bring public opinion to the point of utter indifference whether men so brutalized are enslaved or not.
Source: The Political Economy of International Relations (1987), Chapter Five, The Politics Of International Trade, p. 171

A Change Is Gonna Come
Song lyrics, Ain't That Good News (1964)