Where did the saying may the best of your today be the worst of your tomorrow come from?

The saying "May the best of your today be the worst of your tomorrow" is often attributed to the Irish, reflecting a sentiment of goodwill and hope for a brighter future. It expresses a wish for someone to experience continual improvement and joy in life, suggesting that today's highs should only serve as a baseline for future happiness. While its exact origin is unclear, it resonates with themes of optimism and encouragement found in many cultures.