Hadith: You have embraced Islam along with your past good deeds

عَنْ حَكِيمِ بْنِ حِزَامٍ رَضِيَ اللَّهُ عَنْهُ، قَالَ: قُلْتُ: يَا رَسُولَ اللَّهِ، أَرَأَيْتَ أَشْيَاءَ كُنْتُ أَتَحَنَّثُ بِهَا فِي الجَاهِلِيَّةِ مِنْ صَدَقَةٍ أَوْ عَتَاقَةٍ، وَصِلَةِ رَحِمٍ، فَهَلْ فِيهَا مِنْ أَجْرٍ؟ فَقَالَ النَّبِيُّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: «أَسْلَمْتَ عَلَى مَا سَلَفَ مِنْ خَيْرٍ».
[صحيح] - [متفق عليه]

Hakīm ibn Hizām (may Allah be pleased with him) reported: I said: "O Messenger of Allah, before embracing Islam, I used to do good deeds, like giving in charity, manumitting slaves, and upholding kinship ties. Shall I be rewarded for those deeds?" The Prophet (may Allah’s peace and blessings be upon him) replied: "You have embraced Islam along with your past good deeds."
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

Hakīm ibn Hizām (may Allah be pleased with him) said: O Messenger of Allah, what is the ruling on the good deeds I used to perform as worship during the Jāhiliyyah (pre-Islamic era of ignorance), like charity, upholding of kinship ties, and freeing slaves? He had manumitted a hundred slaves and gave a hundred camels in charity. Will I obtain a reward for them? The Prophet (may Allah’s peace and blessings be upon him) replied: Your past good acts are recorded for you, and you will be rewarded for them. If a disbeliever embraces Islam, his past good deeds be accepted and counted for him. But if he dies as a disbeliever, his good deeds are rendered worthless. Allah Almighty says: {Whoever rejects the faith, all his efforts will be worthless.} [Surat al-Mā’idah: 5]