Jesus is answering his disciples as he “sat on the Mount of Olives” (vs 3). They are asking “when will these things be” after Jesus has shared a shocking prediction about Herod’s great temple that then currently stood in Jerusalem. As they had been leaving the temple complex his disciples were admiring the temple buildings when Jesus said, “there will not be left here one stone upon another that will not be thrown down” (vss 1-2).
Jesus goes on to speak about what will happen “immediately after the tribulation of those days” (vs 29) by describing His return. He relates and explains the parable about the fig tree to them being able to identify the occurrence of “these things” (vs 33). He then says, “this generation will not pass away until all these things take place” (vs 34).
Jesus continues with a “But…” to contrast the timing of His coming – “that day and hour no one knows” – not even Himself (vs 36).