3:1-2 Paul returned to the report of his plans (2:17-18). He explained that by the time he, Silas, and Timothy had reached Athens they felt they could not stay away from their young converts in Thessalonica any longer. They decided that Timothy should return. Silas evidently went back to Philippi and or Berea (Acts 18:5). Paul may have described Timothy as he did here to give this young brother more stature in the eyes of the Thessalonians. Timothy's mission was to strengthen and encourage the new Christians in their faith so the persecution they were experiencing would not discourage them excessively.
Paul may have chosen to send Timothy rather than to return personally for any number of reasons. Timothy was the junior member of the missionary team, and Paul and Silvanus were the senior members. Timothy had a Greek father and probably looked Greek. He would, therefore, have attracted no special interest in a Greek city whereas Paul was immediately recognizable as a Jew (cf. Acts 16:20).60
3:3-5 Often new believers, and even older believers, interpret difficulty as a sign that they need to change something. Timothy reminded them that persecution is a normal experience for the Christian (cf. Matt. 5:11-12; 10:16-28; 20:22-23; 24:9-10; et al.), just as Paul had previously instructed them. Had the Thessalonians fallen before this temptation they would have been in danger of becoming like rocky soil in which the seed of the gospel does not root firmly. Thus the ministry expended on them would have been in vain in the sense that it would not have resulted in substantial growth and fruit.
