1 Thessalonians 1:5

1:5 in that our gospel did not come to you merely in words, but in power and in the Holy Spirit and with deep conviction (surely you recall the character we displayed when we came among you to help you).

1 Thessalonians 3:5

3:5 So when I could bear it no longer, I sent to find out about your faith, for fear that the tempter somehow tempted you and our toil had proven useless.