We cannot know for certain how long we have here. We cannot foresee the trials or misfortunes that will test us along the way. We cannot know God's plan for us.
What we can do is to live out our lives as best we can with purpose, and love, and joy. We can use each day to show those who are closest to us how much we care about them, and treat others with the kindness and respect that we wish for ourselves. We can learn from our mistakes and grow from our failures. And we can strive at all costs to make a better world, so that someday, if we are blessed with the chance to look back on our time here, we can know that we spent it well; that we made a difference; that our fleeting presence had a lasting impact on the lives of other human beings.
--Barack Obama's eulogy for the late Sen. Edward Kennedy