There's a beautiful verse in the Bible, addressed to Christian believers. "Be steadfast, immovable," it says, "always abounding in the work of the Lord, knowing that your labour is not in vain in the Lord" (1 Cor 15:58).
One day I walked into a supermarket, whistling as I went (Sometimes people tell me they can hear me coming before they see me).
"You sound happy," said an assistant on the meat counter. "I am," I said. "I'm one of the happiest people around." "Why? Have you come up on the pools?" "No," I said. "Better than that." "Are you getting married?" "No," I said. "Better than that." "Are you getting divorced?" "No," I said. "Better than that."
"Well," he said, "are you going to tell us the secret, or what?" "Well," I said, "if you like." I told him I had accepted Christ, I knew my sins were forgiven, I had a home in heaven, and I had a peace that only a Christian can know.
We talked for a while; then he told me that some months before two girls from Operation Mobilisation had gone into the shop where he was working, had told him about Christ and had left him some literature.
Next time I went into the supermarket, he was missing. I never saw him again. Sometimes you meet people who are ready to accept Christ themselves. Other times, you're just a link in a chain.
But if you are prepared to speak for Jesus and do things for Jesus, He will arrange the circumstances. And the things you speak and the things you do won't be in vain. They'll be part of His purposes.