It states (Koheles 3:14), מלפניו שיראו עשה והאלקים, "Hashem made we should fear Him." The Zohar (vol.3 98:) says this pasuk refers to Rosh Hashanah. Hashem established Rosh Hashanah, so we should learn to fear Him.
A pesky fly was bothering the Chazon Ish. His shamesh tried to shoo the fly away, but it kept returning. The Chazon Ish said, "Leave it. It is a Rosh Hashanah fly." He was saying that it was destined from Rosh Hashanah that this fly should bother him, and therefore, shooing it away wouldn’t help.
This is the basic emunah of a Yid, to know that everything that occurs was destined and determined on Rosh Hashanah.
We say in the Rosh Hashanah tefillah, עולם הרת היום. The Rokeach explains that הרת means pregnancy because everything that happens during the year has its origin - its pregnancy - on Rosh Hashanah.
Reb Eliyahu Dessler zt'l said, "I am not a heaven person. I don't know what was decreed on Rosh Hashanah. But after the year passes, I know exactly what was decreed last Rosh Hashanah."
Someone was niftar from pneumonia in the middle of the winter in Shevat. Reb Chaim Shmuelevitz zt'l said, "He didn't die from the cold and pneumonia. He was niftar from when the sun shone brightly – when his fate was determined on Rosh Hashanah."
There was a time when there was an international financial crisis, and all wealthy people were worried about their wealth. Reb Yosef Weinberg zt'l was a rich person, a relative to the Slonimer Rebbes zt'l, and he wasn't worried at all. The Beis Avraham of Slonim asked him, "How do you remain calm when all wealthy people are so worried." He replied, "I laugh at these matters. My yerid (market day) is Rosh Hashanah!"
The Beis Avraham zt'l repeated this story many times. Reb Yosef Weinberg correctly understood that what happens in the middle of the year isn’t when it truly occurs. Everything is determined on Rosh Hashanah.
Fishermen cast a large net into the sea with bait inside. Two fish swam into the net, ate the bait, and tried to leave after a while, but they couldn't; they were trapped. One fish told its friend, "We were foolish for spending so much time in the net. We should have taken the bait and left immediately." The other fish replied, "After we took the bait, we were already trapped."
The nimshal is that throughout the year, disappointing things occur, and people often say, "Had I been more careful, this wouldn't have happened." But those with emunah know that it didn't occur now. It was destined and decreed on Rosh Hashanah.
Rosh Hashanah is called (Tehillim 81:4), ,חגינו ליום בכסה "a concealed holiday." The Chofetz Chaim explains that it is called a concealed holiday because the results of the awesome judgment are hidden from us until they happen.
In Radin, before tekiyas shofar, there was a break (as in many batei midrashim). Some said Tehillim, some studied mussar, and almost everyone prepared themselves for the upcoming holy mitzvah. However, some bachurim took advantage of the break to see what was happening in other batei midrashim in Radin. They wanted to see how many people were in each beis medresh, who were the chazanim, and other trivial matters.
The Chofetz Chaim heard about this, and before tekiyas shofar, he spoke. He told a story that happened when he was young. The mother of a bachur of the yeshiva was niftar, and no one knew how to break this news to the bachur. The father sent a telegram advising that they buy a new suit for his son and place a note in one of the pockets informing the bachur what happened to his mother. The bachur was very happy with his new suit. He wore it proudly, but didn't know what was in the pocket. The Chofetz Chaim said that this is the meaning of חגנו ליום בכסה; there is a message concealed in the yom tov. We are happy, light, and cheery, but there is a concealed message, and we don't know yet what it is.
The Gemara (Rosh Hashanah 18.) states, "On Rosh Hashanah, everyone goes before Hashem like מרון בני. The Gemara asks, "What does bnei maron mean?" "Here, in Bavel, we say that it means אמרנא כבני, like sheep." This refers to sheep who pass one by one through a narrow gate for maasar. Every tenth animal is hit with red dye to indicate that this animal is maasar, and it will be brought as a korban. Now, the sheep are all playing together, frolicking in the pasture. If the one with the red dye knew what it meant (that he would soon be slaughtered), he wouldn't be so happy. Similarly, people are happy, but what is concealed? What is the decree? That is hidden from us.
One of my grandfathers, Reb Hershkovitz zt'l, told a mashal of a person who was niftar. The chevrah kadisha placed his body on the floor of a beis medresh and covered it with a talis. The niftar had a young son, and the boy was playing in the beis medresh. He began playing with the strings of the talis. Someone told him, "If you knew what was hidden underneath, you wouldn’t play with this talis." This is the meaning of חגנו ליום בכסה; something is concealed.
But everything can be overturned with teshuvah, tefillah, and tzedakah.
