Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "Whatever a person holds when he accepts Islam belongs to him."
Abu Ya'la recorded it. Its chain contains a narrator, Yasin bin Mu'adh al-Zayyat, who is matruk (abandoned). Some hadith of this kind have already passed in the chapters on zakah and elsewhere.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجهاد / 9721