The Jews leave Egypt and are THIRSTY! Moshe cries out to Hashem. Then it says "ויורהו ה' עץ". What does that mean? Targum Yonason says that Hashem SHOWED him [like "להראות"] a tree that was bitter and Moshe wrote Hashem's name on it. He threw it in the water and the water was sweetened.
Targum Unkelos has another interpretation. He says that "ויורהו" comes from the word "הרואה" - teaching. Hashem TAUGHT him the tree. How does a tree "teach" and what is the lesson?
If we put the two Targums together we can say that Hashem taught Moshe that even the MOST BITTER tree can create intense sweetness if one just attaches Hashem's name to it. [See "Birkas Mordechi". And see also "Menachem Tzion" on the pasuk who connects this tree to the עץ חיים היא למחזיקים בה]. Dr. Viktor Frankel famously taught that with an attachment of meaning, any situation can be tolerated and even celebrated.
Rav Yisrael Meir Lau tells about a Jew who was in the Holocaust and the Nazis used bleach to clean his lice infested body. It burned like anything but this person related that he connected this experience to the love of Hashem. He said that at that point he experienced such pleasure at those moments that he has never been able to equal it since. It was like intense, מעין עולם הבא, dveykus.
Not only that, it is teaching that one should bring even the "bitter" people back to Hashem, not only the elite. As the Ishbitzer says:
