If you're going to remain true to Christ in the midst of trouble and trial you need a proper ministry of God's Word.  In this passage the Holy Spirit, through the Apostle Paul, tells us what that kind of ministry looks like.  The Thessalonians were having some doubts about Paul's, Silas's and Timothy's ministry among them.  After all, when their preaching provoked a riot they left town and they hadn't returned!  Paul answers those doubts by challenging these converts to reflect on the character of the team's ministry and, in the process, he gives us the contours of  how to minister the gospel.