He didn’t say it to us. He wasn’t speaking to us. In any way. He was speaking, according to ‘Mark’, 30-40 years later, to His disciples. So, if He was the real deal in every textual regard, what He said came to pass one way or another. And it did in no uncertain terms for Jewish Christians in 70 AD. Up to a million people died in the First Jewish War. The siege of Masada stretched the Roman army, treasury, state to breaking point. The logistics of attacking a desert mountain fortress with fifteen thousand men for three months was ruinous. There was no water, no wood, no food.
The rational, natural explanation is that ‘Mark; wrote it after 70 AD. Which doesn’t mean that Jesus wasn’t the real deal. ‘Mark’ wasn’t. But let’s assume they both were. Josephus - an eye witness of sorts - backs that up with his 78 AD publication of angelic cavalry manoeuvres and other utterly spine tingling accounts. Others here have argued on the authority of Tom Wright that Jesus’ coming was going; going to Heaven in a local fly-by air display. Begrudgingly I have to accept that. The Greek allows it.
We read - I did for 30 years - our modern eschatological, chiliad (so did the RCC a thousand years ago, hence the Crusades) desperation back in to ‘Mark’. As for the disciples, apostles, Christians from 31-70 AD, they expected Jesus’ imminent return and… moved on when it didn’t happen. According to dubious late Pauline and Petrine epistles.
Whatever the truth, it has nothing to do with now, whenever that is.