The Rebbe the Tzemach Tzedek used to refer to the Rizhiner as “the holy one, the Rizhiner”.

I heard from his holiness… the rebbe… of righteous memory, [= a reference to Rabbi Joseph Isaac Schneersohn, the sixth Lubavitcher rebbe] that the Tzemach Tzedek sent R. Isaac Homler, of righteous memory (who was a gaon and tzaddik and ranked among the most distinguished hasidim of the Alter Rebbe, the Mitteler Rebbe, and the Tzemach Tzedek) on a mission to the tzaddik of Rizhin… and he arrived on Friday. The Rizhiner Rebbe would constantly smoke a Turkish pipe, and every Friday before candle lighting his assistant would come to his courtyard to tell him that the Sabbath was approaching and then he would extinguish his pipe. R. Isaac related that when the assistant came to the room to notify him that the Sabbath was approaching, he saw that the holy R. Israel… remained above [in the higher spiritual realms] and he [R. Isaac] remained below. R. Isaac added that he never felt so ashamed and humiliated.

I.F.

Copied from a letter by R. Shmarya Gourarie to the Agudas Ha-admorim on the occasion of the melave malka in honor of the [yartzeit of the] Rizhiner, 3 Cheshvan 5711