While I believe that this universe is not our final home and am therefore not worried about the eventual disappearance of consciousness from this universe, there exists the clear principle that we should "seek the welfare" (words from Jeremiah 29:7) of humanity for as long as we are here. We shouldn't need the Bible or any other book to remind us of that, of course, as it's really common sense that we should be concerned for the wellbeing of our progeny, and our fellow humans in general, if we have any love at all for others.
While Earth is amazingly rich in resources, it is finite. Expanding into the Solar System (and perhaps beyond) will allow us to tap many more resources and broaden our experience. The human spirit seems designed to continually push boundaries, explore, and grow.
That being said, I'm not sure if it will be a good thing to raise children in low-gravity planetary environments such as the Moon and Mars, as it's quite possible that those children may not be able to tolerate 1g as adults and thus be unable to move to Earth if they desire. Artificial worlds, of course, will be able to rotate in order to simulate 1g.
I'll admit that, with advanced brain-machine interfaces, AI, and constant stimulation, I'm a little worried that no one will be interested in going anywhere. Maybe everyone will just stay in life-support cocoons and explore virtually. In any case, I'm hopeful that people will still ask deep questions about their existence and seek to know their Creator.
