'Happen' in the Bible

Now they were on the road going up to Jerusalem, and Jesus was going on ahead of them. And they were astounded, but those who were following [him] were afraid. And taking aside the twelve again, he began to tell them the things that were about to happen to him:

Truly I say to you that whoever says to this mountain, 'Be lifted up and thrown into the sea!' and does not doubt in his heart, but believes that what he says will happen, it will be [done] for him.

"Tell us, when will these [things] happen, and what [will be] the sign when all these [things] are about to be accomplished?"

And when you hear about wars and rumors of wars, do not be alarmed. This must happen, but the end [is] not yet.

But pray that it will not happen in winter.

For [in] those days there will be tribulation of such a kind as has not happened from the beginning of the creation that God created until now, and never will happen.