Matt 24:14,
This gospel of the kingdom shall be preached in the whole world as a testimony to all the nations, and then the end will come.
2 Thess 2:8,
Then that lawless one will be revealed whom the Lord will slay with the breath of His mouth and bring to an end by the appearance of His coming.
Jesus will not come again until the gospel of the kingdom is preached "in the whole world as a testimony", and the "lawless one will be revealed."