Talmud do Pirke Awot 2:15

Repent one day before your death. How so? Rabbi Eliezer’s students asked him: But does a person know what day he will die, so that he could repent? He said to them: All the more so should he repent every day, for perhaps he will die the next day! And the result is that he repents all of his days! Rabbi Yosei bar Yehudah said in the name of Rabbi Yehudah son of Rabbi Ilai, who said this in the name of his father Rabbi Ilai, who said it in the name of Rabbi Eliezer the Great, (Repent one day before your death, and) warm yourself before the fire of the sages, but be careful not to get burned by their coals. For their bite is like the bite of a fox, and their sting is like the sting of a scorpion, and all of their words are like fiery coals.