From Sahih Bukhari (Hadith 6550):
Narrated Anas: Haritha was martyred on the day (of the battle) of Badr while he was young. His mother came to the Prophet (ﷺ) saying, "O Allah's Messenger (ﷺ)! You know the relation of Haritha to me (how fond of him I was); so, if he is in Paradise, I will remain patient and wish for Allah's reward, but if he is not there, then you will see what I will do." The Prophet (ﷺ) replied, "May Allah be merciful upon you! Have you gone mad? (Do you think) it is one Paradise? There are many Paradises and he is in the (most superior) Paradise of Al-Firdaus
Reference: Bukhari 6550