1 Thessalonians 2:10-11; 1 Thessalonians 5:2; 1 Thessalonians 5:4

10 You are witnesses, and so is God, how devoutly and uprightly and blamelessly we behaved toward you believers; 11 just as you know how we were exhorting and encouraging and imploring each one of you as a father would his own children,
2 For you yourselves know full well that the day of the Lord will come just like a thief in the night.
4 But you, brethren, are not in darkness, that the day would overtake you like a thief;