Soundness of the hadith which says that Allah, may He be glorified and exalted, descends on the night of the fifteenth of Sha‘baan to the lowest heaven
Question

A`isha, the Mother of Believers (may Allah be pleased with her), said: “One night, I did not find the Prophet in his bed, so I went out searching for him and found him at al-Baqi’ cemetery with his head raised towards the sky. He said: ‘O ‘A`isha! Were you afraid that Allah and His messenger would treat you unfairly?’ I said, ‘No, I thought you had gone to spend the night with one of your [other] wives’ He said: ‘Allah Almighty descends to the lowest heaven on the night of mid-Sha’ban and forgives more people than the number of hairs on the hides of the sheep of Bani Kalb1. Authenticity of this Hadith please?
Praise be to Allah.This version of the hadith was narrated by Ahmad (26018), at-Tirmidhi (736) and Ibn Maajah (1389) from ‘Aa’ishah who said: I missed the Prophet (blessings and peace of Allah be upon him) one night, so I went out and I found him in al-Baqee‘, raising his head towards heaven. He said, “O Aa’ishah, were you afraid that Allah and His Messenger would wrong you?” She said: I said: I thought that you had gone to one of your other wives. He said: “Verily Allah, may He be glorified and exalted, descends on the night of the fifteenth of Sha‘baan to the lowest heaven, and He forgives more (people) than the number of hairs on the sheep of Bani Kalb.”
This hadith was classed as da‘eef (weak) by al-Bukhaari, at-Tirmidhi, al-Albaani and the commentators on al-Musnad (ar-Risaalah edn.)
At-Tirmidhi said: We do not know this hadith of ‘Aa’ishah except through this isnaad, from the hadith of al-Hajjaaj, and I heard Muhammad [i.e., al-Bukhaari] class this hadith as da‘eef and saying: Yahya ibn Abi Katheer did not hear from ‘Urwah, and al-Hajjaaj ibn Artaah did not hear from Yahya ibn Abi Katheer. End quote.
The commentators on al-Musnad said: Its isnaad is da‘eef because of the weakness of Hajjaaj ibn Artaah and because it is interrupted. End quote.
It says in Tuhfat al-Ahwadhi (3/365):
“were you afraid that Allah and His Messenger would wrong you?” means: Did you think that I would wrong you by giving your share [of my time] to someone else? That is contrary to the character of one who is a Prophet.
“I said: O Messenger of Allah, I thought that you had gone to one of your other wives” for some reason, and I wanted to verify that. What made me do that is this jealousy that affects women and makes them irrational, not able to think of the consequences of rebukes and the like.
To sum up: I did not think that Allah and His Messenger would wrong me or anyone else; rather I thought that because of a command from Allah or your own reasoning, you had left me and gone to one of your wives, because usually you offer the naafil prayers in your house. …
“and He forgives more (people) than the number of hairs on the sheep of Bani Kalb” means: the tribe of Banu Kalb. They are singled out for mention because they had more sheep than the rest of the Arabs. End quote.
The origin of this hadith is sound, except for the additional material having to do with the fifteenth night of Sha‘baan. It was narrated by Muslim (974) and an-Nasaa’i (2037) from ‘Aa’ishah, who said:
Shall I not narrate to you from me and from the Messenger of Allah (blessings and peace of Allah be upon him)?
We said: Yes.
She said: When it was my night when the Messenger of Allah (blessings and peace of Allah be upon him) was with me, he came in and took off his cloak, took off his shoes and put them by his feet, spread the edge of his waist wrapper on his bed and lay down. He waited until he thought that I had gone to sleep, then he picked up his cloak slowly, put on his shoes slowly, opened the door slowly, and went out, then he closed it slowly. I put my chemise over my head and veiled myself, and wrapped my waist wrapper around me, then I set out following him, until he reached al-Baqee‘ where he stood for a long time, then he raised his hands three times. Then he set off, so I set off, then he hastened, so I hastened, then he jogged, so I jogged, then he ran so I ran, then I reached home before him and went in.
No sooner had I laid down but he came in and said: “What is the matter, O ‘Aa’ishah? Why are you out of breath?”
I said: It is nothing.
He said: “Either you tell me or the Subtle One, the All-Aware will tell me.”
I said: O Messenger of Allah, may my father and mother be sacrificed for you! And I told him.
He said: “So you were the person that I saw in front of me?”
I said: Yes.
He gave me a painful shove on the chest, then he said: “Did you think that Allah and His Messenger would be unjust to you?”
She said: Whatever the people conceal, Allah knows it; yes.
He said: “Jibreel came to me when you saw. He called me but he concealed it from you, and I answered him but I concealed it from you. He would not enter upon you when you were not fully dressed. I thought that you had gone to sleep and I did not want to wake you up, and I was afraid that you might be frightened. He said: “Your Lord is commanding you to go to the people of al-Baqee’ and pray for forgiveness for them.”
I said:  What should I say to them, O Messenger of Allah? He said:
“Say: Peace be upon the people of these abodes, believers and Muslims. May Allah have mercy on those of us who have gone on before and those who come later, and we will – if Allah wills – join you soon.” 
An-Nawawi (may Allah have mercy on him) said in Sharh Muslim (7/43):
“Whatever the people conceal, Allah knows it; yes” – this is how it appears in the original reports, and it is sound. It is as if when she said, “Whatever the people conceal, Allah knows it,” she confirmed what she had said by saying, Yes. End quote.
For more information, please see fatwa no. 140084.
And Allah knows best.