It was all a big misunderstanding. God's attitude toward time is a bit careless, since it means nothing to Him. He told Jesus The End would come in the spring, but He failed to mention the year, or even the millenium. Jesus assumed the Big Guy meant the coming spring. So that's why Jesus was rushing around, trying to get crucified and resurrected in a timely manner, telling everyone "Behold, I come quickly. You people better sleep with your clothes on, because the time is at hand."
But it was all a big misunderstanding. In more ways than one. For starters, God did not say to Jesus, "You need to get crucified, Son. You are the sacrificial Lamb." What He said was "You need to get laid, Son. You're as jittery as a lamb at Passover."
The whole episode was a comedy of miscommunication. And it still hasn't been cleared up, two millenia later. Jesus told everyone He was the Lamb of God and got Himself crucified. So They pretty much had to go with that. They were hoping no one would notice the mistake on the the end of the world timing.
So now God is like, "Jesus Christ, Jesus. Can't you get anything straight? You were only supposed to preach fire and brimstone to them. You were supposed to tell them they have about as much chance of beating the system as a camel has of crawling through the eye of a needle. I intended for all of them to pay for their sins, but you had to go and offer yourself up as a sacrifice, and gave them an out. Now they can repent after sinning like the dirty little sinners they are, and get off the hook. You moron."
And Jesus is like, "You see? This is why we don't talk. You. Always with the negative vibes. It ain't no big thing. So we have to build some condos in heaven to house the repenters. There won't be that many of them, and you never did specify exactly how long "eternity" is. We can just stop the clocks after a while and tell them their time is up, eternity is over, they'll have to move out. And with the earth destroyed, the only available housing is in Hell. If they say anything about how short eternity was, we can say time flies when you're having fun in heaven. Eternity goes by just like that. Whoosh."
And then God glares at Jesus and says (on the inside) "Things would be so much better if that crafty Satan were The Son instead of the bumbling Jesus, with the nail scars in his hands and thorn scars on his forehead. What a maroon." And Jesus says, "I heard that. You keep forgetting, I'm omnipotent too. I can read minds too, Daddy Dearest. And another thing, Dad. I've been studying Satan's rebellion. I know where he messed up. He could have had you, Dad."