Vayechi

 The Rabbis in Pesachim 51b comment on Yaakov saying, "Gather and I will tell you what will happen in the end of days/" They explain, "Yaakov wanted to reveal the end of days and the Divine Presence was removed from him.  The Zohar asks why we are told that Yaakov set out to do something if in the end he didn't do it.  Rather it must be that his will was at least somewhat fulfilled, that he revealed what he needed to reveal and hid that which needed to be hidden  The Zohar says that the words of the Torah are
never flawed, meaning that if the Torah tells us that Yaakov said the words,הֵאָֽסְפוּ֙ וְאַגִּ֣ידָה לָכֶ֔ם אֵ֛ת אֲשֶׁר־יִקְרָ֥א אֶתְכֶ֖ם בְּאַחֲרִ֥ית הַיָּמִֽים then these words were fulfilled and |Yaakov did reveal something, just that he also concealed something.

We can explain this based on the Beis Avraham (may his merit protect us), citing R Shmuel of Kaminka (circa 1771- 1830): The words for I will tell you - וְאַגִּ֣ידָה לָכֶ֔ם - ca also be read to mean that Yaakov was telling them to gather together (the root eged can mean to tell or to bind). in regard to what was going to happen to them, because that will become particularly important in the end of days.  The Rabbis say in Sanhedrin 91a that if we merit it the redemption will come quickly, and if we don't merit that it will come by an assigned deadline.  Yaakov Avinu was giving advice for the situation of not meriting - as of yet - the redemption to be hastened. He was telling them that by uniting they could transition into being considered as meriting the redemption even though they were otherwise in the general state of not meriting it.  

There is a tradition of holy teachers that the verse, "And your nation are all righteous/tzadikim" means that when the individuals of the G-d's nation are all united together as one then they are in the realm of being tzadikim.   The Noam Elimelech explains (in Parshat Devarim) that there is a distinct world called Kol Yisrael, which is the world of the Jewish People in its entirety. And in that realm there is no accidental or purposeful din, no Satan, no negative occurrence that can reach the |Jewish People. Chata'im/"sins" are only for individuals, because individuals sometimes sin, but the Jewish People as a whole always remain in their state of holiness.  And this is the secret that Yaakov revealed, which was all that was necessary for him to share- that even when the Jewish People are in the category of "not meriting," the thing to do is to gather together and unify and transform into the entity of Klal Yisrael as a whole.  Through this switch they can access the energy of meriting the redemption.

(The start of the piece, on page 313 of Breishit NS from heading till the end of the page)