General Dought clear, - * The last ten nights of Ramadan begin from the night before the twenty first day, whether the month is complete or not

I have a question that arose from something that one of my friends
said about the last ten nights of Ramadan. My friend said: If Ramadan
is twenty-nine days, then the last ten days are from the nineteenth to
the twenty ninth. So how can I know the odd-numbered nights among
them? What is your response to that?
-
Praise be to Allah
The last ten nights of Ramadan begin from the night before the twenty
first day, whether the month is thirty days or is twenty-nine days.
This is indicated by the report narrated by al-Bukhaari (813) and
Muslim (1167) from Abu Sa'eed al-Khudri who said: The Messenger of
Allah (blessings and peace of Allah be upon him) observed i'tikaaf
during the first ten days of Ramadan, and we observed i'tikaaf with
him. Then Jibreel came to him and said: "What you are seeking is ahead
of you." So he observed i'tikaaf during the middle ten days, and we
observed i'tikaaf with him. Then Jibreel came to him and said: "What
you are seeking is ahead of you." So the Prophet (blessings and peace
of Allah be upon him) stood up and addressed us on the morning of the
twentieth of Ramadan and said: "Whoever observed i'tikaaf with the
Prophet (blessings and peace of Allah be upon him), let him come back,
for I was shown Laylat al-Qadr then I was caused to forget it. Verily
it is in the last ten nights, on an odd-numbered night, and I saw
myself prostrating in mud and water." The roof of the mosque was made
of palm leaves, and we had not seen anything in the sky, but then a
cloud came and it rained, and the Prophet (blessings and peace of
Allah be upon him) led us in prayer until I saw the traces of mud and
water on the forehead of the Messenger of Allah (blessings and peace
of Allah be upon him) and the tip of his nose, in fulfilment of his
dream.
According to a report narrated by al-Bukhaari (2027), the Messenger of
Allah (blessings and peace of Allah be upon him) used to observe
i'tikaaf during the middle ten days of Ramadan. One year he observed
i'tikaaf until on the night of the twenty first, which was the night
on the following morning of which he would come out of his i'tikaaf,
he said: "Whoever was observing i'tikaaf with me, let him observe
i'tikaaf for the last ten nights, for I was shown this night then I
was caused to forget it, and I saw myself prostrating in water and mud
on the following morning. So seek it in the last ten nights, and seek
it on every odd-numbered night." It rained that night, and the mosque
was 'covered with palm leaves, so the mosque leaked, and I saw with my
own two eyes the Messenger of Allah (blessings and peace of Allah be
upon him) with traces of water and mud on his forehead, on the morning
of the twenty-first.
Al-Haafiz (may Allah have mercy on him) said:
This clearly shows that this speech was given on the morning of the
twentieth day, and the rainfall occurred on the night before the
twenty first.
End quote fromFath al-Baari(4/257)
According to a report narrated by al-Bukhaari (2018) and also Muslim
(1167), it says: The Messenger of Allah (blessings and peace of Allah
be upon him) used to stay in the mosque (for i'tikaaf) in Ramadaan, in
the ten days in the middle of the month, then on the evening of the
twentieth, before the twenty first, he would go back to his home, and
those who had stayed in the mosque with him also went back home.
This indicates that the last ten days begin from the night before the
twenty first.
Hence the view of the majority of scholars – including the four imams
– is that whoever wants to observe i'tikaaf during the last ten nights
of Ramadan should enter the mosque before sunset on the night before
the twenty-first.
See the answer to question no. 14046.
The odd-numbered nights of the last ten are the nights before the
twenty-first, twenty-third, twenty-fifth, twenty-seventh and
twenty-ninth.
The night before the nineteenth is not included among the odd-numbered
nights of the last ten, regardless of whether the month is complete or
incomplete (i.e., thirty or twenty-nine days), because it is one of
the middle ten.
Al-Haafiz Ibn Hajar (may Allah have mercy on him) said:
Laylat al-Qadr can only be in Ramadan, then in the last ten nights of
it, then in the odd-numbered nights of those ten, not on any specific
night among them. This is what is indicated by all the reports that
have been narrated concerning it.
End quote fromFath al-Baari(4/260)
And Allah knows best.