1 Thessalonians 1:5
5 because our gospel came to you not simply with words but also with power, with the Holy Spirit and deep conviction. You know how we lived among you for your sake.
“The Holy Spirit changes people when they believe the gospel. When we tell others about Christ, we must depend on the Holy Spirit to open their eyes and convince them that they need salvation. God’s power changes people—not our cleverness or persuasion. Without the work of the Holy Spirit, our words are meaningless. The Holy Spirit not only convicts people of sin but also assures them of the truth of the gospel. (For more information on the Holy Spirit, see John 14:23-26; 15:26, 27; and the notes on John 3:6 and Acts 1:5.)” (Life Application Study Bible 2015)
Life Application Study Bible. Zondervan, 2011. p. 2015.