Then I saw a new heaven and a new earth.
The former heaven and the former earth had passed away,
and the sea was no more.
I also saw the holy city, a new Jerusalem,
coming down out of heaven from God,
prepared as a bride adorned for her husband.
Romantics think of history and human life as organic. Hearing of God's promise, of a new heaven and a new earth, they suppose these mysteries must appear as surely as the sun rises in the morning, as surely as Spring follows Winter which follows Autumn.
And the Church often uses these natural signs to describe the fulfillment of God's word. I love Isaiah's reassuring poem:
...just as from the heavensBut we trust in God's promises not because we have seen the natural cycles of our circling planet but because we believe in God.
the rain and snow come down
And do not return there
till they have watered the earth,
making it fertile and fruitful,
Giving seed to the one who sows
and bread to the one who eats,
So shall my word be
that goes forth from my mouth;
It shall not return to me empty,
but shall do what pleases me,
achieving the end for which I sent it.
The Communists were romantics; they believed that "history" must inevitably bring down the mighty and raise up the lowly, that the proletariat would have an innate wisdom and integrity which were foreign to the wealthy and powerful. They believed -- pathetically as it turns out -- in Nature rather than God.
That 19th century idealism finally collapsed at the end of the 20th century though it survives in various liberal movements. Many people still believe democracy and capitalism will inevitably, organically create a just and peaceful world -- if only certain selfish people would get out of the way. These romantic notions are sometimes called determinism, and they persist among many atheistic scientists who cannot find freedom in their test tubes.
We believe in the promises of God because we believe God is faithful and true. In the darkest hour of our despair we saw him raise up Jesus and seat him at his own right hand in heaven!
How God's other promises will be fulfilled we do not pretend to imagine. It seems they are as often accomplished by setbacks as by advances. No one really knows whether this unexpected development or that is a success or a failure; and I suspect God doesn't know the meaning of those words. Success and failure are theoretical criteria, not real, existing only in men's minds. They cannot be used to measure anything in God's mysterious plans.
What we can expect of God is the unexpected; we can expect to find grace in disappointment and darkness in light. We can be sure that, no matter what happens, God is still in charge.