I made a comment in the
previous posting that, " The first recorded case was in fact Zimri - who was the first kiruv rabbi who fell in the line of duty - trying to convert the non-Jewish princess." RaP questioned by noting that Avraham was the first kiruv rabbi. The answer is simply that Zimri was the first kiruv rabbi who died because of his kiruv techniques.
Below are some of the discussion of Rav Tzadok of the problem of confusing lust with holiness. It is a major theme of his and he brings in such topics as Amalek and Esther's relationship with Achashveros as well as Rabbi Akiva and why ultimately the Oral Torah is from converts.
Rav Tzadok also notes that sexual lust is a major problem for those studying kabbala because there are many sexual concepts. In fact a number of years ago there was a kabbalist in the Old City who had a study group with women and it was discovered he was having intimate relations with a number of them.
Rav Tzadok(Machshavos Charutz #4): Zimri went to Moshe with the defense, “And who permitted the daughter of Yisro to you?” In other words Zimri was defending his sexual activity with Kosbi as being permitted to him as being a spiritual activity in the same way that Tzipora was permitted to Moshe. This is according to the explanation of the Arizal that Kosbi had the soul of Dina and Zimri was convinced that all his lusts were genuine spiritual desires in accord with the Torah…
Rav Tzadok(Likutei Amarim #16): Zimri went to Moshe with the defense, “And who permitted the daughter of Yisro to you?” That is when Moshe married Tzipora she had not yet converted since she was under the control of her father Yisro to the degree that the Mechilta says that Yisro insisted to Moshe that his first son should be for idolatry – conversion came later…
Rav Tzadok(Takanas HaShavim #6): Dina was incarnated in Kosbi whose father was the source of evil of Midian who wanted to destroy the Jews so that they would be like all the other nations. But Kosbi didn’t listen to her father and wanted to convert if Zimri was interested. This is the meaning of Zimri’s claim, “Who permitted Tzipora to you?” Zimri grabbed Kosbi by her hair in the manner of the Amorites while she was still a non‑Jew because he was the incarnation of Shechem and he sensed that there are souls of non‑Jews that come into to Jews and non‑Jews who have Jewish souls. He thought that by having intercourse with Kosbi he would collect the holy sparks that were in her while she was still a non‑Jew.
Rav Tzadok(Takanas HaShavim #15): Zimri meant by his defense to Moshe, “And who permitted the daughter of Yisro to you?” that the children he had with Kosbi would be considered Jews. Thus he was doing a sin for the sake of Heaven which is like a mitzva not for the sake of Heaven (Nazir 23b)…