"Brothers we do not want you to be ignorant... For the Lord himself will come down from heaven...and the dead in Christ will rise first. After that, we who are still alive and are left will be caught up..." (1 Thessalonians 4:13-18). We do not know times and dates, "But you, brothers, are not in darkness so that this day should surprise you... He died for us so that...we may live together with him." (1 Thessalonians 5:4, 10).
"Concerning the coming of our Lord Jesus Christ... Don't let any one deceive you in any way, for that day will not come until the rebellion occurs and the man of lawlessness is revealed... whom the Lord Jesus will overthrow..." (2 Thessalonians 2:1, 3, 8). The lawless one will display all kinds of counterfeit miracles, signs and wonders - it sounds a little like events leading up to the exodus out of Egypt in Exodus chapters 7-10.
Paul may have expected the second coming during his life time, nearly 2000 years ago! The time may come at any time. In the mean time Paul encourages us to be patient, live in peace with one another and work - don't be lazy!