Likutei Moharan 61:7/ליקוטי מוהר"ן ס״א:ז׳

17. This is the reason people travel to the tzaddikim <of the generation> for Rosh HaShanah. Rosh HaShanah is the Judgment Day of the entire year. Each person comes with his holiness and constrictions to the tzaddik of the generation. He is the aspect of holy of holies/Foundation Stone, in the aspect of “For the pillars of the earth are God’s; He has founded the world upon them” (1 Samuel 2:8). These are the tzaddikim, upon whom the earth was founded. Thus by [traveling to the tzaddikim], all severe judgments are mitigated through the aspect of the Foundation Stone, as explained above.

2This is likewise the aspect of Yaakov’s stones, which were all encompassed in the Foundation Stone (Zohar I, 231a). For the souls are the aspect of stones, as it is written (Lamentations 4:1), “The holy stones have been strewn about.” They all come and are encompassed in the tzaddik of the generation, who is the aspect of the Foundation Stone. And through this all the constrictions are mitigated, as explained above.