Paul had urged the believers to walk in a manner worthy of God; he was also careful to remind them that their obedience did not ultimately depend on their ability and merit. God is active in their lives since he is the one who calls you into his kingdom and glory. God’s call is an effective call which powerfully accomplishes its aims. Because God had chosen the Thessalonian believers, he called them through the gospel and they turned from idols to serve the living and true God (2 Thessalonians 2:13–14; 1 Thessalonians 1:4–5; 1 Thessalonians 1:9–10; see also Romans 8:28–30). In the same way, God’s ongoing call would ensure that they would remain faithful to the end, becoming thoroughly sanctified in body, soul, and spirit (1 Thessalonians 5:23–24). It is the ongoing aspect of this call which led Paul to use the present tense here in 1 Thessalonians 2:12, though the decisive initial call had occurred at the time of their conversion.1,2
This understanding of God’s effectual call, which continues in the present experience of God’s people, would have motivated and encouraged the Thessalonian believers to walk in holiness and obedience. An understanding of this call would have assured them that they were not simply obeying God’s commands by their own strength in order to earn his approval; rather, God was at work in them to will and to act according to his good purpose (Philippians 2:13).
12 we exhorted each one of you and encouraged you and charged you to walk in a manner worthy of God, who calls you into his own kingdom and glory.