Isaiah 40b - Why Should I be Faithful to God?

In this second part of chapter 40, Isaiah deals with some of the most fundamental questions of religion and belief in God. Why bother having faith if we don't see justice? Why should I go on in life if we all die anyway? Why does God sometimes punish and sometimes reward? Why would such a great and powerful behind even care about one small human being? Does He even care about little me?