Sayyiduna Salamah bin Yazid al-Ju'fi (may Allah be pleased with him) narrated: My brother and I came to the Messenger of Allah (peace and blessings be upon him) and said: O Messenger of Allah, our mother, in the Days of Ignorance, used to be hospitable to guests and maintain the ties of kinship. Will that deed of hers benefit her in any way? He (peace and blessings be upon him) said: "No." We said: She buried a sister of ours alive who had not yet reached puberty? So the Messenger of Allah (peace and blessings be upon him) said: "The girl buried alive and the woman who buried her will both be in Hell, unless the one who buried her lives to see Islam and accepts it."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6291