This quote is by Oswald Chambers: “The aim of the missionary is to do God’s will, not to be useful, not to win the heathen; he is useful and he does win the heathen, but that is not his aim. His aim is to do the will of his Lords.”
So often as a missionary it’s easier to lose our focus and to get our eyes on other things. Low attendance or no attendance, slow growth in the work, tight budgets, cultural differences, and a myriad of other things take our focus off of what our main goal is: to honor and glorify God by doing His will and not our own.