It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "If three children of a Muslim husband and wife die before reaching puberty, they will become a strong fortress for them against Hell." Someone asked: O Messenger of Allah! What if someone has lost two children? The Prophet (peace and blessings be upon him) said: "The same ruling applies." (Sayyiduna Abu Dharr Ghifari (may Allah be pleased with him) said: O Messenger of Allah! I have sent forth two children? He replied: "The same ruling applies.") Sayyiduna Ubayy ibn Ka'b (may Allah be pleased with him) — who is famous as the leader of the reciters — said: Only one of my children has died? People asked the Prophet (peace and blessings be upon him): O Messenger of Allah! What if someone has lost one child? The Prophet (peace and blessings be upon him) said: "This matter relates to the initial moments of grief" (that is, who is patient at that time and who is not, because later everyone becomes patient).
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 3554
Hadith Gradingحکم دارالسلام:في إسناده بهذه السياقة ضعف وانقطاع، محمد بن أبى محمد مجهول، وأبو عبيدة لم يسمع من أبيه