Genesis 15:5-6 (ESV)And he brought him outside and said, "Look toward heaven, and number the stars, if you are able to number them." Then he said to him, "So shall your offspring be." And he believed the Lord, and he counted it to him as righteousness.
Several things strike me about this. 1) If you're having trouble believing God's promises, maybe you need a change of scenery. Get out of the tent and look up. Look at your life from God's point of view. A lot of times we get a sort of spiritual cabin fever. Our lives close in on us and we have trouble seeing the bigger picture. 2) When we step out on faith and believe God's promises, it means more to God than moral living. Good deeds don't equal righteousness; faith equals righteousness!
Right after that, God gives Abram full disclosure:
Genesis 15:12-13 (ESV)As the sun was going down, a deep sleep fell on Abram. And behold, dreadful and great darkness fell upon him. Then the Lord said to Abram, "Know for certain that your offspring will be sojourners in a land that is not theirs and will be servants there, and they will be afflicted for four hundred years."
God tells Abram that just because he made a promise of a great legacy to Abram, doesn't mean the road will always be easy or pleasant. This is a HUGE thing for us to remember. God has made many promises to us. Some have been completed and some we're still waiting for. What we need to remember is that if bad things happen in our lives, it doesn't mean that God has broken his promises. We see the hear and now and feel momentary pain, but God sees the BIG picture. Stay faithful, because God is faithful!
In fact, in ch. 16 we see Abram and Sarai get impatient with God and take the dream into their own hands. The results were disastrous. Not only in what we read in the Biblical account, but even still today. The descendants of Ishmael and the descendants of Isaac have been warring for thousands of years. God's way is ALWAYS best, even if we can't see it or understand it. Wait on the Lord!