beat two birds with one stone

KILL TWO BIRDS WITH ONE STONE - "Achieve two objectives with a single effort."

It would be remarkable indeed if someone slinging a stone at a bird got one bird, let alone two.

Ovid had a similar expression in Latin nearly 2,000 years ago.
Related phrases were in English and French literature by the 16th century.
Thomas Hobbes used the modern version in a work on liberty in 1656:
'T. H. thinks to kill two birds with one stone, and satisfy two arguments with one answer.'" "Dictionary of Cliches" by James Rogers (Wings Books, Originally New York: Facts on File Publications, 1985).