'Labour' in the Bible

But if I live in the flesh, this is the fruit of my labour: yet what I shall choose I wot not.

Therefore, my dearly-loved friends, as I have always found you obedient, labour earnestly with fear and trembling--not merely as though I were present with you, but much more now since I am absent from you--labour earnestly, I say, to make sure of your own salvation.

the word of life holding forth, for rejoicing to me in regard to a day of Christ, that not in vain did I run, nor in vain did I labour;

Yet I supposed it necessary to send to you Epaphroditus, my brother, and companion in labour, and fellowsoldier, but your messenger, and he that ministered to my wants.