Saeed bin Jubair (may Allah have mercy on him) narrated that I said to Ibn Abbas (may Allah be pleased with him): "Nauf Bikali claims that the companion of Khidr, Musa (peace be upon him), was not Musa (peace be upon him) of Bani Israel." So Ibn Abbas (may Allah be pleased with him) said: "By Allah! The enemy of Allah has lied." Ubayy bin Ka'b (may Allah be pleased with him) told me, he said that the Messenger of Allah (ﷺ) delivered a sermon to us, then he (ﷺ) narrated the long hadith about the incident of Musa and Khidr, which indicates that Musa (the Prophet, peace be upon him) was indeed the companion of Khidr.
Hadith Referenceمسند الإمام الشافعي / كتاب فضائل قريش وغيرهم وأبواب متفرقة / 1793
Hadith Takhrijاخرجه البخاری، احادیث الانبياء، باب حديث الخضر مع موسى عليهما السلام (3401) ومسلم، الفضائل، باب من فضائل الخضر (2380)۔