Revelation 1:7
Behold, he cometh with clouds; and every eye shall see him, and they also which pierced him: and all kindreds of the earth shall wail because of him. Even so, Amen.
This verse specifically refers to the RETURN of Christ to earth. This great event is known as the "revealing" or "revelation" of Christ when he returns as King of Kings and Lord of Lords as discribed in Revelation 19:11-16. It is important to note that this is NOT the rapture. The rapture is the churches departure as seen in Revelation 4:1.
"And all kindreds of the earth shall wail because of him". This is because here we see the Second Coming of Christ when he returns with his saints (Revelation 19) to execute judgement on all (Jude verses 14 & 15).
"Even so, Amen", interestingly the Greek for even so is "Amen" and the Hebrew for "Amen" is even so.