1 Thessalonians 3:5
For this cause, when I could no longer forbear, I sent to know your faith, lest by some means the tempter have tempted you, and our labour be in vain. For this cause, when I could no longer forbear, I sent to know your faith, lest by some means the tempter have tempted you, and our labour be in vain.
Unable to visit in person and no longer able to forbear, Paul sent to learn the state of the faith of the Thessalonian believers while they were passing through trial and adversity. His urgency came from concern lest Satan, the tempter as an active enemy, had tempted them away from faith, so that his labor for them would prove empty and in vain. When word came that they had remained true to God, he was cheered. In this he sets the pattern that faithful workers keep watch for the spiritual safety of those they serve.