Strong emphasis is placed on God who calls. He cares about people and is so eager to bring them into his glorious kingdom (1 Thessalonians 2:12). Therefore he urgently calls them away from all sexual impurity, (the Greek word for impurity (ἀκαθαρσία) indicates sexual sins) and longs for his called ones to live holy and pure lives. That is also possible because he who calls you is faithful; he will surely do it
(1 Thessalonians 5:24).
7 For God has not called us for impurity, but in holiness.