Paul says we are to “comfort” these weak-spirited brothers and sisters.
“Comfort” is from the Greek word, paramutheomai, which means “to draw alongside to instruct.” It is often translated “encourage” or “console.” We see it in John 11:19, 31 describing how Mary and Martha’s friends came to “comfort” them when their brother Lazarus died.
In I Thessalonians 2:11 Paul used this word to describe his relationship to that church, “As ye know how we exhorted, and comforted, and charged every one of you, as a father doth his children.” It means to draw near and say what is needed to strengthen them. He says in 2:7, “But we were gentle among you, even as a nurse (mother) cherisheth her children.”
Roman 15:1 says, “We then that are strong ought to bear the infirmities of the weak, and not to please ourselves.” Galatians 6:2 says, “Bear ye one another’s burdens, and so fulfill the law of Christ.”
Many in the Thessalonian church were “fainthearted” and in need of “comfort.” If you study this letter along with the book of Acts, you learn that this church was born under and constantly faced great persecution. They paid a great price for their faith in Christ.
Just like a father with a hurting child, strong believers are to “comfort” others who may be fearful.