The pasuk says in Sefer Zecharyah, ביום ההוא יהיה ה' אחד ושמו אחד - in the future, "Hashem will be one." The Gemara asks the obvious question, isn't Hashem one even now? The answer, the Gemara explains, is that now it appears that Hashem sometimes deals with us lovingly and compassionately, but at other times harshly and unfairly. In the future, however, we will see how He is always dealing with us kindly and mercifully. It will become clear to us that everything He does is driven by deep love and concern.
People who understand this never get upset or agitated, because they do not need to wait until the future to see Hashem's mercy even during hard times. They believe this even now, with all their heart and soul.
Rabbi Lugassi told a story which he heard firsthand, about a Rabbi in Israel who taught Torah to many students, and also managed to run a jewelry business. Some 40 or 50 years ago, this Rabbi wanted to pray at the gravesite of Rabbi Shimon bar Yohai at Meron, and he asked one of his students to travel with him. The student was overjoyed at the opportunity to spend so much time with his beloved Rabbi, and enthusiastically agreed.
Along the way, the Rabbi decided to do some business. He was fluent in Arabic, and he stopped to meet with Arab merchants and purchase merchandise which he could then sell for a profit. He took nearly all the money he had, and even borrowed some money, anticipating opportunities to purchase quality merchandise at low prices. Sure enough, he found very special jewelry, and he spent all the money he had. He kept the merchandise in his suitcase which he had with him at all times, never letting it out of his sight.
This Rabbi's practice when he visited Meron was to first go up to a mountain by himself to mentally prepare himself. He told his student to carefully watch his suitcase while he was gone, explaining how valuable the suitcase was and warning him never to take his hands or eyes off of it for even a second.
In the meantime, however, two thieves were following the Rabbi and his student, eyeing the suitcase. They devised a shrewd plan to distract the student and take the suitcase, and the plan worked.
When the student realized that the suitcase was gone, he started trembling. He ran around frantically searching for it, but it was nowhere to be found.
The Rabbi returned, and the student, with tears flowing from his eyes and his spirit broken, apologetically reported that the suitcase was stolen.
The Rabbi's immediate response was to ask the student whether he had eaten lunch. The student, wondering why the Rabbi was asking about lunch now, said that he had not yet eaten. The Rabbi told him he had brought food with him from Jerusalem, and they sat down to eat together. All throughout, the Rabbi said not one word about the stolen suitcase. They went to the gravesite, and the Rabbi prayed there as if nothing unusual had happened. The student later recalled that the Rabbi never mentioned to him anything about the suitcase.
Not only did the Rabbi not berate or shout at the student, he made a concerted effort to calm him by offering him lunch. The student described how this Rabbi lived with genuine faith that everything which happens is from Hashem and is for the best, and so even under the most trying circumstances, he accepted Hashem's will without complaint and without anger. This Rabbi went on to achieve great spiritual heights, and other Rabbis attributed his greatness to his success in overcoming this test when his merchandise was stolen. Even though the Rabbi did not see how the loss of his merchandise was good, he believed it, and this was enough for him.
Rabbi Tauber told that he was once invited to speak words of inspiration to several audiences in the Diaspora, including at a very large event where he was scheduled to be the keynote speaker. As he waited at the gate to board his flight from Israel, an announcement was made informing the passengers that the flight would be delayed four hours. The delay meant that he would miss the main event where he was to have delivered the keynote address.
As soon as the announcement was made, the passengers began angrily complaining about how they were going to miss meetings, appointments and other scheduled events. The people were all in an uproar. Rabbi Tauber, however, sat in his seat calmly, learning from a book, as if nothing happened.
A certain Jewish professor who was there took note of Rabbi Tauber's conduct, and observed how the Rabbi sat there calmly without any reaction. He decided to approach the Rabbi and ask how he could remain so calm and exhibit no signs of agitation. Rabbi Tauber explained that although he'd be missing an important speech that he was supposed to give, the Torah teaches that Hashem is in full control, and everything is for the best, whether or not we understand how. The four-hour delay was thus caused by Hashem, and it must therefore be for the best. As such, there was no reason to be upset.
Some 15 years later, the professor happened to meet Rabbi Tauber again, and asked if he remembered him. The Rabbi answered in the negative, and the professor reminded him of their exchange at the airport.
The professor, who now wore a kippah and a beard, said, "That day, when I saw how you remained so calm at the airport, I decided to explore Torah. I was so inspired by you, and I ended up becoming a ba'al teshuvah.
Rabbi Tauber said, "For years I was trying to think how missing an opportunity to give an inspirational speech to a large crowd of people could have been a good thing. I never found the answer until today. This delay resulted in my bringing another Jew back to Hashem."
Everything has a reason, and the reason is always good. If we trust Hashem, we will always have peace of mind.