Mu'jam Kabir Tabarani 12170 — Seven (relations) are forbidden

Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates: "Seven (relations) are forbidden on account of lineage, and seven are also forbidden on account of marriage ties." Then he recited this verse: "Forbidden to you are your mothers" [Surah al-Nisa: 23] until he reached "and the daughters of the sister" [Surah al-Nisa: 23], then said: "This is the prohibition by lineage." Then he recited this verse: "And your mothers who nursed you" [Surah al-Nisa: 23] until he reached "and that you combine two sisters together" [Surah al-Nisa: 23], then he recited this verse: "And do not marry those women whom your fathers married" [Surah al-Nisa: 22], then said: "This is the prohibition by marriage ties."