“Now will I show myself to have more of the serpent than the dove”
Christopher Marlowe The Jew of Malta
Barabas, Act II, scene iii. Marlowe is referencing Jesus, "Be ye therefore wise as serpents, and harmless as doves," in Matthew 10:16.
The Jew of Malta (c. 1589)
Context: Now will I show myself to have more of the serpent than the dove; that is, more knave than fool.