Al-Muttalib bin Abdullah al-Makhzumi relates: I went to Sayyidah Umm Salamah (may Allah be pleased with her), the honoured wife of the Prophet (peace and blessings be upon him), and she said: "O my son! Shall I not tell you a hadith that I heard from the Prophet (peace and blessings be upon him)?" I said: "Yes indeed, O mother!" She said: "I heard the Prophet (peace and blessings be upon him) say: 'Whoever spends on two daughters, or two sisters, or two female relatives, hoping for reward for spending on them, and keeps spending until, by the grace of Allah Almighty, the two of them (girls) become self-sufficient or are provided for, the two of them will become a barrier shielding that person from Hell.'"
Imam Ahmad and Imam Tabarani recorded it; its chain contains a narrator, Muhammad bin Humayd al-Madani, and he is da'if (weak).