This parable comes from Rabindranath Tagore.
"I was going begging from door to door along the street of the village when Your gilded chariot appeared in the distance. It was like a dream, a splendid thing, and I admired Him who was the King of Kings. My hopes rose high and I thought: this is the end of my misery. I was already sure that I would receive large alms, offered spontaneously, and that coins would be scattered about me in the dust.
Your chariot stopped where I was standing. Your glance fell upon me and You alighted and smiled at me. I felt that the chance of a lifetime had come to me.
Then suddenly, You held out Your hand and said to me, "What have you to give to me?"
Eh? What royal game was this? To come begging from a beggar?
I was bewildered and then perplexed and finally, from my sack, I took a tiny grain of wheat and I gave it to you.
You went on your way, but what was my surprise when, at the end of the day, I emptied my sack out on the ground, I found a grain of gold amid the grains of wheat.
Then did I weep and I thought: why did I not have the courage to give You all that I had!"