The night of Isra’ and Mi’raaj (the Prophet’s Night Journey and Ascent into heaven) are two great signs of Allaah and there is no doubt in that.
It points to the truthfulness of Allah's Messenger and his great status before his Lord. They are also signs of the great power of Allaah, and of His exalted position above His creation. Allaah says (interpretation of the meaning):
“Glorified (and Exalted) be He (Allaah) [above all that (evil) they associate with Him]
Who took His slave (Muhammad) for a journey by night from Al‑Masjid Al‑Haraam (at Makkah) to Al‑Masjid Al‑Aqsa (in Jerusalem), the neighborhood whereof We have blessed, in order that We might show him (Muhammad) of Our Ayaat (proofs, evidences, lessons, signs, etc.). Verily, He is the All‑Hearer, the All‑Seer”
The share reports from the messenger of Allah indicate that he was taken up into heavens and their gates were opened for him until he reached the seventh heaven where Allah directly spoke to him. At this time he was gifted with the 5 daily prayers upon him. At first, 50 prayers were enjoined but later it was reduced to 5 because our Prophet kept on going back and asked Allah to reduce it, so they are five obligatory prayers but fifty in reward because each good deed is rewarded tenfold. To Allaah be praise and thanks for all His blessings.
With regard to the night on which Isra and Mehraj took place, there is no sound evidence that supports that it happened in the month of Rajab or in any other month. Everything else that suggest its date does not come from Prophet Muhammad(peace be upon him) and cannot be proven to have come from him. Allaah has wise reasons for causing the people to forget it.
Even if the dates were proven it still is not valid or permissible to celebrate it because there is no mention of its celebration in authentic sources of knowledge. The Prophet Muhammad(peace be upon him) didn't celebrate it. The sahaba didn't celebrate it. They didn't single out a day and celebrated it in any way. If celebrating it was something of any importance or mandatory then there would have been its mention in hadith of Prophet Muhammad(peace be upon him). If any such thing had happened, it would have been well known, and his companions would have transmitted the information to us.
They have narrated to us everything that Prophet Muhammad peace be upon him taught them or told them. They never neglected any of his commands and in fact were the ones to do anything that was required of a Muslim to do.
If the celebration of this night was prescribed in Islam they would have been the first ones to do so and would have narrated to us.
The Prophet (peace and blessings of Allaah be upon him) was the most sincere of people, and he conveyed the message to the people in full, and he fulfilled the trust. If venerating and celebrating this night were part of the religion of Allaah, then the Prophet (peace and blessings of Allaah be upon him) would have done that and would not have concealed it.
Since there is no such thing, and no such celebrations took place, taking part in any way on this day is not permissible at all. It is not part of Islam. Allaah has perfected this ummah’s religion for it and has completed His favour upon them, and He condemns those who introduce things into the religion which Allaah has not ordained. Allaah says in His holy Book, in Soorat al-Maa’idah (interpretation of the meaning):
“This day, I have perfected your religion for you, completed My Favour upon you, and have chosen for you Islam as your religion”
And Allaah says in Soorat al-Shoora (interpretation of the meaning):
“Or have they partners with Allaah (false gods) who have instituted for them a religion which Allaah has not ordained?”
It is proven in saheeh hadith that prophet Muhammad peace be upon him has warned his Ummah against bidah or introducing things in Islam. He has clearly stated that this is misguidance and how great the punishment of Allah is upon the innovator. It was to show the ummah how serious the matter is and put them off it.
It is narrated in al-Saheehayn from ‘Aa’ishah (may Allaah be pleased with her) that the Prophet (peace and blessings of Allaah be upon him) said: “Whoever introduces anything into this matter of ours that is not part of it will have it rejected.” In a report narrated by Muslim it says: “Whoever does any action that is not part of this matter of ours will have it rejected.”
In Saheeh Muslim it is narrated that Jaabir (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) used to say in his khutbah on Friday: “The best of speech is the Book of Allaah and the best of guidance is the guidance of Muhammad (peace and blessings of Allaah be upon him). The worst of matters are those which are newly-invented, and every innovation is a going astray.” Al-Nasaa’i added with a jayyid isnaad: “and every going astray will be in the Fire.”
In al-Sunan it is narrated that al-‘Irbaad ibn Saariyah (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) delivered an eloquent speech to us which melted our hearts and caused our eyes to flow with tears. We said: O Messenger of Allaah, it is as if it is a farewell address, so advise us. He said: “I advise you to fear Allaah, and to listen and obey, even if a slave is appointed over you. Whoever among you lives will see many differences, so I urge you to adhere to my Sunnah and the way of the rightly-guided caliphs who will come after me, and cling firmly to it. Beware of newly-invented matters, for every newly-invented matter is an innovation and every innovation is a going astray. And there are many ahaadeeth with a similar meaning.
Such warninga against bidah have been narrated from the companions of the messenger of Allah peace be upon him as the bidah is nothing more than adding matter into islam that Allah has not ordered. It is an imitation of enemies of Allah like the Jews and Christians who continually added things to their religion that were not prescribed to them. They considered themselves to be more knowledgeable.
Following or introducing a bidah also implies that there is something Lacking in Islam or that Prophet Muhammad peace be upon him left the teachings of Islam incomplete. It is well known that such beliefs will lead to mischief and evil on land.
Also taking part in bidah also means that a person goes against this verse believing that Allah has left the deen incomplete. May Allah forgive us.
Allaah says (interpretation of the meaning): “This day, I have perfected your religion for you, completed My Favour upon you, and have chosen for you Islam as your religion” [al-Maa’idah 5:3] It also goes against the ahaadeeth of the Messenger (peace and blessings of Allaah be upon him) which warn against innovation (bid’ah). We hope that the above evidence is enough and sufficient for the one who is seeking the truth. It should convince anyone who is trying to find answers that this bid’ah is wrong, i.e., the innovation of celebrating the night of the Isra’ and Mi’raaj, and that it is not part of the religion of Islam at all. Because Allaah has enjoined being sincere towards the Muslims and explaining what Allaah has prescribed for them in their religion, and because it is haraam to conceal knowledge, we thought that we should point out this innovation, which is so widespread in many regions that people think it is part of the religion, to my Muslim brothers. Allaah is the One Whom we ask to set the affairs of all the Muslims straight, and to bless them with knowledge of Islam, and to help us and them to adhere steadfastly to the truth, and to forsake everything that goes against it, for He is able to do that. May Allaah send blessings and peace upon His slave and Messenger, our Prophet Muhammad, and his family and companions. And Allah knows best.