Midrasz do Wyjścia 4:8

"And He said to him: 'therefore, whoever kills Kayin" (Gen. 4:15) - Rabbi Yehudah and Rabbi Nechemiah. Rabbi Yehudah says: the domestic animals, the wild ones and the fowl entered to demand justice for the blood of Hevel. He said to them: therefore I say 'whoever kills Kayin will be killed'. Said Rabbi Levi: the Primordial Snake entered to demand justice for the blood of Hevel.The Holy One of Blessing said to him: therefore I say 'whoever kills Kayin will be killed'. Rabbi Nechemiah says: Kayin's judgment is not like the judgment of the rest of the murderers, Kayin killed and had no one to learn from, from here onwards 'whoever kills Kayin will be killed'. "And Ad-nai put on Kayin a sign" (Gen. 4:15) - Rabbi Yehudah and Rabbi Nechemiah. Rabbi Yehudah said: He made the Sun shine for him. Said Rabbi Nechemiah: to that evil one the Holy One of Blessing would make the sun shine?! Rather, it teaches that He made tzara'at [a scaly skin condition] shine on him! As you say: 'and if they do not believe you or pay heed to the first sign, [they will believe the second.'] (Exodus 4:8) Rav said: He gave him a dog. Aba Yosi ben Keisari said: He made a horn sprout on him. Rav said: He made him an example for murderers. Rabbi Chanin said: He made him an example for ba'alei teshuvah [penitents, returners, Heb. also shavim]. Rabbi Levi in the name of Rabbi Shime'on ben Lakish said: He suspended his judgment until the Flood came and drowned him, as it is written 'and He blotted out all those standing on the face of the land' (Gen. 7:23), just as you say 'And Kayin stood up/rose' (Gen. 4:8)