بسم اللــــه الرحمـــــــــن الرحيم
Shaykhul Islam Ibn Taymiyyah -raḥimahullāh- was asked:
When should we look out for Laylatul Qadr?
So he responded (paraphrased):
Laylatul Qadr occurs during the last ten nights of Ramaḍhān, as is authentically established from the Prophet ﷺ; who said:
.((تَحَرَّوْا لَيْلَةَ الْقَدْرِ فِي الْعَشْرِ الأَوَاخِرِ مِنْ رَمَضَانَ))
“Look out for Laylatul Qadr during the last ten nights of Ramaḍhān.”
[Reported by Bukhāri & Muslim on the authority of ‘Ā’ishah -raḍhiyallāhu ‘anhā]
And In the version of Bukhāri, he ﷺ specifically said:
.((تَحَرَّوْا لَيْلَةَ الْقَدْرِ فِي الْوِتْرِ مِنَ الْعَشْرِ الأَوَاخِرِ مِنْ رَمَضَانَ))
“Look out for Laylatul Qadr during the odd nights of the last ten nights of Ramaḍhān.”
However, it is important to note that there are two ways of calculating the odd nights:
1-THE FIRST:
By counting the days that have already passed; such that Laytul Qadr could fall on the 21st, 23rd, 25th, 27th, or the 29th night of Ramaḍhān.
or
2 – THE SECOND:
By counting the days that remain, just as the Prophet ﷺ said:
.((الْتَمِسُوهَا فِي الْعَشْرِ الأَوَاخِرِ مِنْ رَمَضَانَ لَيْلَةَ الْقَدْرِ فِي تَاسِعَةٍ تَبْقَى، فِي سَابِعَةٍ تَبْقَى، فِي خَامِسَةٍ تَبْقَى))
“Look out for the Laylatul Qadr during the remaining ten nights of Ramaḍhān; on the night when nine or seven or five nights remain.”
[Reported by Bukhāri on the authority of Ibn Abbās -raḍhiyallāhu ‘anhumā]
So according to this method, if Ramaḍhān consisted of 30 days -and only Allāh knows if this will be the case- Laylatul Qadr will fall on one of the even nights, because the 22nd will be the night when nine remain, the 24th will be the night when seven remains and the 26th will be the night when five remains.
And this was the understanding of Abū Sa‘īd Al-Khudri -raḍhiyallāhu ‘anhu-:
Muslim reported that Abun Naḍhr enquired:
يَا أَبَا سَعِيدٍ! إِنَّكُمْ أَعْلَمُ بِالْعَدَدِ مِنَّا. قَالَ: أَجَلْ! نَحْنُ أَحَقُّ بِذَلِكَ مِنْكُمْ. قَالَ: قُلْتُ: مَا التَّاسِعَةُ وَالسَّابِعَةُ وَالْخَامِسَةُ؟ قَالَ: إِذَا مَضَتْ وَاحِدَةٌ وَعِشْرُونَ فَالَّتِي تَلِيهَا ثِنْتَيْنِ وَعِشْرِينَ وَهْىَ التَّاسِعَةُ، فَإِذَا مَضَتْ ثَلاَثٌ وَعِشْرُونَ فَالَّتِي تَلِيهَا السَّابِعَةُ، فَإِذَا مَضَى خَمْسٌ وَعِشْرُونَ فَالَّتِي تَلِيهَا الْخَامِسَةُ
“O Abū Sa‘īd, you know more than us about (these) numbers. He said: Yes, indeed we have better right than you. I said: What is this ninth, seventh, and fifth? He said: When 21 (nights are over) and the 22nd begins, it is the ninth, and when 23 (nights) are over, that which follows (i.e. the 24th) is the seventh, and when 25 nights are over, what follows (i.e. the 26th) is the fifth”.
If, however, Ramaḍhān consists of 29 days, then these two forms of calculations will be exactly the same.
This being the case, it is befitting that the believer works hard throughout the last ten nights of Ramaḍhān (without confining themselves to the odd nights), just as the prophet ﷺ said:
((تَحَرَّوْا لَيْلَةَ الْقَدْرِ فِي الْعَشْرِ الأَوَاخِرِ مِنْ رَمَضَانَ))
“Look out for Laylatul Qadr during the last ten nights of Ramaḍhān.”
[Reported by Bukhāri & Muslim on the authority of ‘Ā’ishah -raḍhiyallāhu ‘anhā]
This is also proven by the practice of the Prophet ﷺ, as ‘Ā’ishah -raḍhiyallāhu ‘anhā- said:
كَانَ النَّبِيُّ ﷺ إِذَا دَخَلَ الْعَشْرُ – أي العشر الأواخر من رمضان – شَدَّ مِئْزَرَهُ، وَأَحْيَا لَيْلَهُ، وَأَيْقَظَ أَهْلَهُ.
“With the start of the last ten days of Ramaḍhān, the Prophet ﷺ would tighten his waist sheet (i.e. work hard and refrain from sexual relations), pray throughout the night, and he would also wake his wives.”
[Reported by Bukhāri & Muslim]
[Majmū‘ Al-Fatāwā (25/284)]