What Is The Moral Of The Fable "The Labourer And The Nightingale"�?

In fact this story has three morals. A labourer heard a nightingale singing in a tree near his home. It was so beautiful that he decided to catch the bird, so that she could sing for him whenever he wished. When he approached her with a net, the nightingale begged to be spared, saying that caged birds wouldn't sing. The labourer refused to listen, and caught her. Once she was caged, the bird said, "If you will let me go, I'll tell you three things worth more than all the songs in the world." The labourer was so curious that he did let her go. Once she was free, she flew into a tree out of reach and said, "One: never believe a captive's promise. Two: keep what you've got. Three: don't grieve for what is lost for ever." With these words she flew away, and he never heard her again.