R. Zussia – “now that I have no more part in the world to come, I can serve You the more lovingly"

I was reading Rabbi Schachter-Shalomi’s responses to some prompts in an old Commentary article (https://www.commentary.org/articles/jacob-agus-2/the-state-of-jewish-belief/) and saw this interesting reference to something Rabbi Zussia said. Sadly he didn’t cite the source and there isn’t much context – I looked around online and searched Sefaria but couldn’t find the original anywhere. Does anyone know if there is a written source in English or Hebrew for these quotes somewhere?

This recklessness is closer to the great Maggid’s “now that I have no more part in the world to come, I can serve You the more lovingly,” than to Calvin’s being damned for G-d’s greater glory. Some of R. Zussia’s readiness to go to hell because “in this I can fulfill one more mitzvah” is stronger than a Kierkegaardian suspension of the ethical.