Tears
The Arizal taught that it is crucial to cry on Rosh Hashanah. The Chasam Sofer says that (Tehillim 89:17) יוםה לכ גילוןי שמךב, "With Your name they rejoice every day," is roshei teivos ה"בכי, crying, because we should cry tears of joy.
Reb Pinchas of Koritz zt'l said that when one is happy, he is able to cry whenever he wants to.
The Gemara (Bava Metzia 59.) states, "From the day the Beis HaMikdash was destroyed, the gates of tefillah were closed, but the gates of tears weren't locked." When we daven with tears, our tefillos are guaranteed to ascend to heaven, and our tefillos will be answered.
Reb Shlomo Kluger zt'l taught that one should pray before Rosh Hashanah that he should be able to cry on Rosh Hashanah. He said that this is alluded to in the pasuk (Tehillim 42), דמעתי לי היתה ...חי ל"לא לאלקים נפשי צמאה. Reb Shlomo Kluger explained, נפשי צמאה, "My heart thirsts; לאלקים, that on the day of judgment, דמעתי לי היתה, I should be able to cry."
The Satmar Rebbe zt'l told the following mashal:
A prince was imprisoned in a distant land because he had rebelled against his father, the king. The queen yearned to see her child, so she traveled a long distance and spoke to him son from outside the prison walls. The son told her about the horrible conditions under which he was imprisoned. The queen took pity on him and threw him a key so he could unlock the gate and go free, but the key didn’t work. "Perhaps it's the wrong key," the prince said. "It’s the right key," she replied. "The problem is you've been in jail very long and the lock is rusty. The only solution is for you to cry. Your tears will wash away the corrosion, and the lock will open." The nimshal is that davening with tears breaks through all heavenly locks and gates.
The Yismach Moshe told the following mashal:
"A king got angry at his servants, and they didn’t know how to appease him. The sar hamashkim (the king's cup-bearer) came up with an idea. "I will serve the king his favorite wine", he said. "The king will become happy and will certainly forgive us." The good wine is our tears. When we shed tears, Hashem is appeased, as it says, בדמעות מתרצה מלך, "The King who is appeased through tears."
Therefore, we say in Selichos, בדמעות מתרצה מלך לפני דמעותינו הכניסו דמעה מכניסי, "[The malachim] who bring in tears, bring our tears before the King who is appeased with tears." We tell the malachim that they can bring our tears before Hashem, but nothing more than that. The malachim can't deal with the tears themselves. This is because the malachim cannot comprehend the depth, sincerity, yearning, and pain of Yiddishe tears; only Hashem alone can. Therefore, only Hashem can receive the tears.
During the Holocaust, the Rebbe of Piaseczna zt'l hy'd said, "Did a malach ever experience the pain of being beaten and hit as Yidden do? Does a malach know the humiliation of being pursued and hunted? Did a malach ever experience hunger pangs?" Therefore, we tell the malachim to daven for us (תחינה והרבה השתדלו), but when it comes to our tears, they should bring them before Hashem.
