Tractate Sanhedrin - Chapter 6 - Mishnah 2 סנהדרין פרק ו׳ משנה ב׳

When he is about ten cubits away from the place of stoning, they say to him, ‘confess’, for such is the practice of all who are executed, that they [first] confess, for he who confesses has a portion in the world to come. For so we find in the case of Achan, that Joshua said to him, “My son, pay honor to the Lord, the God of Israel, and make confession to him. [Tell me what you have done, do not hold anything back from me.” And Achan answered Joshua and said, “It is true, I have sinned against the Lord the God of Israel, and this is what I have done” (Josh. 7:19-20). And how do we know that his confessions made atonement for him? As it says, “And Joshua said, “What calamity have you brought upon us! The Lord will bring calamity upon you this day” (Josh. 7:35), [meaning] this day you are a calamity, but you are not to be a calamity in the next world. And if he does not know how to confess, they say to him, “Say, may my death be an expiation for all my sins.” Rabbi Judah said: “If he knows that he is a victim of false evidence, he can say: may my death be an expiation for all my sins but this.” They [the sages] said to him: “If so, everyone will speak likewise in order to clear himself.”