Mishkat al-Masabih 1:112

Abud Darda' reported God’s messenger as saying, “God created Adam when He created him and struck his right shoulder and brought forth his offspring white like small ants. And he struck his left shoulder and brought forth his offspring black as though they were charcoal. Then He said to the party on his right side, ‘To paradise, and I do not care’ and He said to the party in his left shoulder, ‘To hell, and I do not care’.” Ahmad transmitted it.