Genesis 21:1-7 NIV
 Now the Lord was gracious to Sarah as he had said, and the Lord did for Sarah what he had promised.  Sarah became pregnant and bore a son to Abraham in his old age, at the very time God had promised him.  Abraham gave the name Isaac to the son Sarah bore him.  When his son Isaac was eight days old, Abraham circumcised him, as God commanded him.  Abraham was a hundred years old when his son Isaac was born to him.  Sarah said, “God has brought me laughter, and everyone who hears about this will laugh with me.”  And she added, “Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age .”
At last! The child of promise has been born. Sarah, after decades of waiting, anxious and frustrated, thinking that God wouldn't come through on His Word, gives birth to Isaac. I wonder how often she looked back at her doubts, mistakes and struggles, asking herself: "Why did you not believe that what God said He would do? Why did you take matters into your own hands? Why were you so fearful and faithless?"
And yet we can all be a bit like Sarah when God seems not to be in as much as a hurry as we are. We think He's forgotten about us. That maybe we've committed some great sin and stepped out of His will and plan for us. We begin to doubt what He previously spoke and ask: "Did God really say...?"
God is always faithful to His Word. ALWAYS. No exceptions, no exclusions. Every circumstance we are facing may seem to contradict this, but we don't live by what we see but by what He says. Our emotions aren't governed by what we witness around us in the world, but by what we read about Him in His Word.
Trust His heart when you can't see His hand. One day you, like Sarah, will look back and laugh. Laugh with joy at His goodness; laugh at yourself and how stressed you once were; laugh at those who mocked you and ridiculed you for believing. I know I look back at those times when I thought God had forgotten about me, when I lost sleep and paced anxiously, spent fruitless days worrying about what lay ahead and I laugh at all my wasted stressing.
He who has been faithful, will be faithful. He who has never failed, will never fail.