Hadith: Allah, the Exalted, says: "My reward shall be nothing less than Paradise for My faithful servant who, if I take the life of his beloved one from the inhabitants of the world, he bears it patiently in expectation of My reward."

عن أبي هريرة رضي الله عنه مرفوعًا: «يقول الله تعالى : ما لِعَبدِي المُؤمن عِندِي جَزَاء إِذَا قَبَضتُ صَفِيَّه مِنْ أَهلِ الدُّنيَا ثُمَّ احْتَسَبَه إِلاَّ الجنَّة».
[صحيح] - [رواه البخاري]

Abu Hurayrah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Allah, the Exalted, said: 'My reward shall be nothing less than Paradise for My faithful servant who, if I take the life of his beloved one from the inhabitants of the world, he bears it patiently in expectation of My reward.'"
[Authentic hadith] - [Narrated by Bukhari]

Explanation

In this Qudsi Hadīth, the Prophet (may Allah's peace and blessings be upon him) says that any believer who is tested with losing his beloved one, whether a relative, such as one's child, parent, sibling, uncle, or one's friend, and he is patient with his loss, seeking reward from Allah, then the reward for it is nothing less than Paradise.