God's Literal Promises

Gen 17:3 Then Abram fell on his face. And God said to him...

Gen 17:8 I will give to you and to your offspring after you the land of your sojournings, all the land of Canaan, for an everlasting possession, and I will be their God."

Those silly Jews think God was being literal when He spoke of an "everlasting possession." He didn't try to mislead Abraham, Isaac, and Jacob into thinking this promised land was a physical place, they just took it that way. Obviously God was being figurative. Right?

1Th 4:16 For the Lord himself will descend from heaven with a cry of command, with the voice of an archangel, and with the sound of the trumpet of God. And the dead in Christ will rise first.
1Th 4:17 Then we who are alive, who are left, will be caught up together with them in the clouds to meet the Lord in the air, and so we will always be with the Lord.

Of course God's Word through Paul is literal. What's to be figurative about this?

I'm mocking you. I'll stop now. My point is that Abraham and all his offspring understood God's promise. Now Christians say they are wrong. If that's the case, how do we as Christians know that our understanding of God's promises aren't also wrong? What if a new sect arises telling us, "Silly Christians! That's figurative!"

Rom 11:18 Do not be arrogant toward the branches. If you are, remember it is not you who support the root, but the root that supports you.

Rom 11:22 Note then the kindness and the severity of God: severity toward those who have fallen, but God's kindness to you, provided you continue in his kindness. Otherwise you too will be cut off.

Wouldn't it be a whole lot more consistent and logical to say that nothing is figurative? That God always means what He says?