כִּ֤י אִם־תְּכַבְּסִי֙ בַּנֶּ֔תֶר וְתַרְבִּי־לָ֖ךְ בֹּרִ֑ית נִכְתָּ֤ם עֲוֺנֵךְ֙ לְפָנַ֔י נְאֻ֖ם אֲדֹנָ֥י יְהוִֽה׃
即使你用鹼水洗濯，又多用皂草，你罪孽的污跡仍然顯在我面前。這是主永恆者說的。
Reshit Chokhmah
It also says in the Zohar in Noach: 57. Come and behold: all of man’s sins and corruption can be atoned for by repentance. But by the sin of spilling his seed on the earth, man corrupts himself and the earth as well. And of such a person, it is written: “The stain of your iniquity is before Me,” (Yirmeyah 2:22) and “For You are not an El that has pleasure in wickedness, nor shall evil sojourn with You” (Tehilim 5:5). THIS MEANS THAT A PERSON WHO WASTES HIS SEMEN ON THE EARTH IS CALLED EVIL, AND HE SHALL NOT SOJOURN ANYMORE WITH THE HOLY ONE, BLESSED BE HE. IN OTHER WORDS, HE SHALL NOT ACCEPT HIS REPENTANCE, except after great penitence. It is also written that “Er, Judah’s firstborn, was wicked in the sight of Hashem; and Hashem slew him” (Beresheet 38:7), as was already explained elsewhere. (Some versions of the Zohar say ‘unless it is with very strong Teshuva’).