'Strenuous' in the Bible

A song of ascents. O Lord, for David's sake remember all his strenuous effort,

Foreigners are consuming what his strenuous labor produced, but he does not recognize it! His head is filled with gray hair, but he does not realize it!

So then God’s choice is not dependent on human will, nor on human effort [the totality of human striving], but on God who shows mercy [to whomever He chooses—it is His sovereign gift].