The idea of being separated bodily (in person) but not in spirit, in heart, or in thought was very common in ancient letters.1 Paul uses the idea to assure the Thessalonians that he had not simply forgotten about them after leaving them: his thoughts (and his prayers—1 Thessalonians 3:11–13) were with them; physical separation did not mean emotional or mental separation.
2
17 But since we were torn away from you, brothers, for a short time, in person not in heart, we endeavored the more eagerly and with great desire to see you face to face,