"And I do this that I may prove unto many that I am the same yesterday, today, and forever; and that I speak forth my words according to mine own pleasure. And because that I have spoken one word ye need not suppose that I cannot speak another; for my work is not yet finished; neither shall it be until the end of man, neither from that time henceforth and forever."
2 Nephi 29:9
Can you imagine being the same ... all the time? Sometimes I feel like I change into a different person, just depending on what song comes on the radio. :) That kind of continuity of self sounds like a remarkable thing to me. I think really, when God asks us to be perfect, that's what he going for... consistently being our best selves. Wouldn't you love it if you could always keep your cool, no matter what? If you could always have the same opinion about yourself, whether you were being criticized or adored? If you could treat people well, no matter what kind of a mood you were in? I would.
The second part of the verse continues this theme... saying that God is always, always, always the same... and then expanding on it, saying... why would you ever think that I would stop talking to my children? It's like saying that Shakespeare's Romeo and Juliet sums up his entire authorship. God still has work to do, children to save... and as some of the ones who are still in the process, we should be glad that he is still answering prayers and talking to prophets, just as he always has. :)