It is a bungling fisherman who strikes at the first nibble; I shall wait till my fish has gorged the bait and then I am sure to land him.
Source, in full
Remarks to his son explaining why he declined to form a government (22 February 1851), quoted in Disraeli, Derby and the Conservative Party: Journals and Memoirs of Edward Henry, Lord Stanley, 1849–1869, ed. John Vincent (1978), p. 44