(13) According to Rabbi Yochanan: The Holy Blessed One has said of Israel: Even though I appointed a deadline for his coming whether or not they repent by the appointed season of arrival; nevertheless, if they repent even for a single day, I will bring her even though it is not the appointed season.
א"ר אלכסנדרי כל העוסק בתורה לשמה ... [רבי יוחנן אמר] אף מגין על כל העולם כולו שנאמר ובצל ידי כסיתיך ולוי אמר אף מקרב את הגאולה שנאמר (ישעיהו נא, טז) ולאמר לציון עמי אתה
Rabbi Alexandri says: Anyone who engages in the study of Torah for its own sake... Rabbi Yoḥanan says: One who engages in Torah study also protects the entire world, as it is stated: “And I have covered you in the shadow of My hand.” And Levi says: He also advances the coming of the redemption, as it is stated: “And say to Zion, you are My people.”
א"ר שמואל בר נחמני אמר ר' יונתן תיפח עצמן של מחשבי קיצין שהיו אומרים כיון שהגיע את הקץ ולא בא שוב אינו בא אלא חכה לו שנאמר אם יתמהמה חכה לו שמא תאמר אנו מחכין והוא אינו מחכה ת"ל (ישעיהו ל, יח) לכן יחכה ה' לחננכם ולכן ירום לרחמכם
Rabbi Shmuel bar Naḥmani says that Rabbi Yonatan says: May those who calculate the end of days be cursed, as they would say once the end of days that they calculated arrived and the Messiah did not come, that he will no longer come at all. Rather, the proper behavior is to continue to wait for his coming, as it is stated: “Though it tarry, wait for it.”
(ב) ... וְכֵן לֹא יְחַשֵּׁב הַקִּצִּין. אָמְרוּ חֲכָמִים תִּפַּח רוּחָם שֶׁל מְחַשְּׁבֵי הַקִּצִּים. אֶלָּא יְחַכֶּה וְיַאֲמִין בִּכְלַל הַדָּבָר כְּמוֹ שֶׁבֵּאַרְנוּ:
(2) ... And similarly one should not calculate the ends. Our Sages have said that the spirit of those who calculate the Ends will expire I.e. They will die.. Rather, one is to (simply) wait ...