expression
in order to; for the purpose of
Formal/literary expression attached to the -nai stem of a verb (e.g., 言わんがため, せんがため). Similar to ために but more bookish and emphatic.
See also: ために
彼は真実を明らかにせんがため、長い調査を続けた。
He continued a long investigation in order to reveal the truth.
成功を収めんがためには、努力を惜しんではならない。
You must spare no effort in order to achieve success.