1 Thessalonians 3:7-13 (NIV)
7 Therefore, brothers and sisters, in all our distress and persecution we were encouraged about you because of your faith. 8 For now we really live, since you are standing firm in the Lord. 9 How can we thank God enough for you in return for all the joy we have in the presence of our God because of you? 10 Night and day we pray most earnestly that we may see you again and supply what is lacking in your faith.
11 Now may our God and Father himself and our Lord Jesus clear the way for us to come to you. 12 May the Lord make your love increase and overflow for each other and for everyone else, just as ours does for you. 13 May he strengthen your hearts so that you will be blameless and holy in the presence of our God and Father when our Lord Jesus comes with all his holy ones.
Matthew 24:42 (NIV)
42 “Therefore keep watch, because you do not know on what day your Lord will come.