to do one's endeavor
Webster's Dictionary (GCIDE)
Endeavor \En*deav"or\, n. [Written also endeavour.] An exertion of physical or intellectual strength toward the attainment of an object; a systematic or continuous attempt; an effort; a trial. [1913 Webster]
To employ all my endeavor to obey you. --Sir P. Sidney. [1913 Webster]
To do one's endeavor, to do one's duty; to put forth strenuous efforts to attain an object; -- a phrase derived from the Middle English phrase "to do one's dever" (duty). "Mr. Prynne proceeded to show he had done endeavor to prepare his answer." --Fuller.
Syn: Essay; trial; effort; exertion. See Attempt. [1913 Webster]