"Into each life some rain must fall" is a proverb which means that everyone has to face difficulties or unpleasant experiences in their lives. It is often used to express sympathy or to give encouragement to someone who is going through a tough time. The proverb is based on the idea that life is not always easy and that everyone will have their share of challenges. However, it also suggests that these challenges can be overcome and that it is important to keep moving forward.