Is the following hadith authentic?
Khateeb Al-Baghdadi narrates a long hadith in ‘Ruwatu Malik’ on an incident that took place with the famous Companion Jabir bin Abdullah. Imam As-Suyuti records it in his Al-Khasa’is Al-Kubra. The portion of this hadith is as follows:
Jabir said:
“The Prophet, sallallaahu 'alayhi wa sallam, took some water for ablution and saw two separate date trees. He, sallallaahu 'alayhi wa sallam, said to me, ‘Oh jabir! Go to them and tell them to get together.’ They got together as if their roots were one. He then made ablution as I brought the water to Him. I then thought in my head, if only Allaah informed me about his, sallallaahu 'alayhi wa sallam, waste, so that I may consume it! I saw that the earth on which he sat was clean. So I asked, ‘Did you not relieve yourself?’ to which he replied, ‘Yes, but the earth is ordered to hide away the excess of us prophets.’ The date trees then separated…” [26]

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.

This hadeeth is not authentic. Al-Kittaani mentioned it in his book entitled Tanzeeh Ash-Sharee’ah Al-Marfoo’ah ‘an Al-Akhbaar Ash-Shanee’ah Al-Mawdhoo’ah, and he stated that Al-Khateeb narrated it in Ruwaat Maalik from Is-haaq ibn As-Salt, and he said, “I did not narrate it from Maalik except with this chain of narrators.”

Also, Ath-Thahabi said in Al-Meezaan, “Is-haaq ibn As-Salt narrated a very objectionable hadeeth from Imaam Maalik [i.e. it was not reported by Maalik], and its chain of narrators is objectionable.”

The origin of the story was narrated by Imaam Muslim in his Saheeh, but the statement of Jaabir that you mentioned in the question: “I then thought in my head, if only Allaah informed me about his () waste, so that I may consume it! I saw that the earth on which he sat was clean. So I asked, ‘Did you not relieve yourself?’ to which he replied, ‘Yes, but the earth is ordered to hide away the excess of us Prophets’…” is not included in the wording of Imaam Muslim. 

Allaah knows best.