Mustadrak al-Hakim — Hadith 9015

It is narrated from Abu Abd al-Rahman al-Sulami; he said: We camped at a distance of one farsakh (about three miles) from al-Mada'in. When Friday came, my father attended and I attended with him. Sayyiduna Hudhayfah (may Allah be pleased with him) addressed us and said: "Indeed, Allah, the Mighty and Majestic, says: 'The Hour has drawn near, and the moon has split.' [Surah al-Qamar: 1] Listen! The Hour has indeed drawn near. Listen! The moon has indeed split. Listen! The world has indeed announced its departure. Listen! Today is the training ground, and tomorrow is the race." I asked my father: Will the people race against one another tomorrow? He said: "O my son! You are ignorant. He only means that today is for deeds and tomorrow is the recompense." Then when the next Friday came, we attended, and Sayyiduna Hudhayfah (may Allah be pleased with him) addressed us and said: "Indeed, Allah, the Mighty and Majestic, says: 'The Hour has drawn near, and the moon has split.' [Surah al-Qamar: 1] Listen! The world has announced its departure. Listen! Today is the training ground, and tomorrow is the race. Listen! The end of this race (for those who fail) is the Fire, and the winner (the one who gets ahead) is the one who races ahead to Paradise."
The chain of this hadith is sahih (authentic), but the two Shaykhs (Bukhari and Muslim) did not record it.