Harithah[RA] is in Jannathul Firdaus, Al A’la
Anas (May Allah be pleased with him) reported: Umm Ar-Rubaiy`i bint Al-Bara’, who was the mother of Harithah bin Suraqah, came to the Prophet (PBUH) and said: “O Messenger of Allah! Will you not tell me about Harithah? (He was killed in the battle of Badr). If he is in Jannah I shall show endurance, but if he has met another fate, I may exert myself in weeping for him.” He (PBUH) replied, “O mother of Harithah, in in the gardens of Jannah there are many ranks, and your son has attained Al-Firdaus, the highest.”
Commentary: Jannat-ul-Firdaus is the highest portion of Jannah. The allocation of this portion to the martyrs is a proof that Jihad is very much liked by Allah. It occurs in Ahadith that when someone prays to Allah, he should always pray for Jannat-ul-Firdaus.