The Waiting Game of Zechariah and Elizabeth

How's the feeling of waiting? Is it easy or difficult? Or sometimes, impossible? Why does God allow us to wait for a long time before we receive that something we are praying for? It might be the career that you've always wanted, the relationship you've been dreaming or the financial prosperity that you badly needed. We serve God, we pray, we continue to attend church and our small group faithfully, but why does God make us wait? How long shall we wait?