"Teach us to number our days, that we may gain a heart of wisdom" (Psalm 90:12).
"Number our days" - what does this mean? Surely, it means that our life on earth will come to an end. How long will my life be? I don't know the answer to this question. How long will your life be? You don't know the answer to this question. "A heart of wisdom" - what does this mean? A lot more could be said about this, but, here, we say just one thing - it's about learning to live in the light of eternity.