Ismail, and I believe he traced it back to the Prophet ﷺ, reported that the Prophet ﷺ said, "Allah has cursed the man who marries a divorced woman to make her lawful for her former husband and the one for whom she is made lawful."
حدثنا أحمد بن يونس حدثنا زهير حدثني إسمعيل عن عامر عن الحارث
إسمعيل وأراه قد رفعه إلى النبي ﷺ أن النبي ﷺ قال لعن الله المحلل والمحلل له
No references are available.
Its isnad is daif. Tirmidhi also narrated it in the chapter on marriage, section on what has been said about the muhill and the one for whom the marriage is made lawful (muhallal lahu), hadith 1119, and Ibn Majah, hadith 1935, from the hadith of Amir Shaybi through this route, and its chain is very daif. The hadith has corroborating narrations found in Ahmad, 2/323, and Ibn Jarud, hadith 684, and others, and the hadith of Ahmad at 2/323 is hasan and serves in its place.