[Machine] The Messenger of Allah ﷺ used to observe i'tikaf during the last ten nights of Ramadan, and he would recite the hadeeth of Yahya.  

كَانَ رَسُولُ اللهِ ﷺ يَعْتَكِفُ الْعَشْرَ الْأَوَاخِرَ مِنْ رَمَضَانَ لَفْظُ حَدِيثِ يَحْيَى  

I observed i'tikaf in the first ten (nights and days) in order to seek that night (Lailat-ul-Qadr). I then observed i'tikaf in the middle ten days. Then (an angel) was sent to me and I was told that this (night) is among the last ten (nights). He who among you likes to observe i'tikaf should do so; and the people observed it along with him, and he (the Holy Prophet) said: That (Lailat-ul-Qadr) was shown to me on an odd (night) and I (saw in the dream) that I was prostrating in the morning in clay and water. So in the morning of the twenty-first night when he (the Holy Prophet) got up for dawn (prayer). there was a rainfall and the mosque dripped, and I saw clay and water. When he came out after completing the morning prayer (I saw) that his forehead and the tip of his nose had (traces) of clay and water, and that was the twenty-first night among the last ten (nights). (Using translation from Muslim 1167c)   

أَنَّ رَسُولَ اللهِ ﷺ اعْتَكَفَ الْعَشْرَ الْأُوَلَ مِنْ رَمَضَانَ ثُمَّ اعْتَكَفَ الْعَشْرَ الْأَوْسَطَ فِي قُبَّةٍ تُرْكِيَّةٍ عَلَى سُدَّتِهَا حَصِيرٌ قَالَ فَأَخَذَ الْحَصِيرَ بِيَدِهِ فَنَحَّاهَا فِي نَاحِيَةِ الْقُبَّةِ ثُمَّ أَطْلَعَ رَأْسَهُ فَكَلَّمَ النَّاسَ فَدَنَوْا مِنْهُ فَقَالَ إِنِّي اعْتَكَفْتُ الْعَشْرَ الْأُوَلَ الْتَمِسْ هَذِهِ اللَّيْلَةَ ثُمَّ اعْتَكَفْتُ الْعَشْرَ الْأَوْسَطَ ثُمَّ أَتَيْتُ فَقِيلَ لِي إِنَّهَا فِي الْعَشْرِ الْأَوَاخِرِ فَمَنْ أَحَبَّ مِنْكُمْ أَنْ يَعْتَكِفَ فَلْيَعْتَكِفْ فَاعْتَكَفَ النَّاسُ مَعَهُ قَالَ وَإِنِّي رَأَيْتُهَا لَيْلَةَ وِتْرٍ وَإِنِّي أَسْجُدُ فِي صَبِيحَتِهَا فِي طِينٍ وَمَاءٍ فَأَصْبَحَ فِي لَيْلَةِ إِحْدَى وَعِشْرِينَ وَقَدْ قَامَ إِلَى الصُّبْحِ فَمَطَرَتِ السَّمَاءُ فَوُكِفَ الْمَسْجِدُ فَأَبْصَرْتُ الطِّينَ وَالْمَاءَ فَخَرَجَ حِينَ فَرَغَ مِنْ صَلَاةِ الصُّبْحِ وَجَبِينُهُ وَرَوْثَةُ أَنْفِهِ فِيهَا الطِّينُ وَالْمَاءُ وَإِذَا هِيَ لَيْلَةُ إِحْدَى وَعِشْرِينَ مِنَ الْعَشْرِ الْأَوَاخِرِ  

when the Messenger of Allah ( ﷺ) decided to observe i'tikaf, he prayed in the morning and then went to the place of his i'tikaf, and he commanded that a tent should be pitched for him, and it was pitched. He (once) decided to observe i'tikaf in the last ten days of Ramadan. Zainab (the wife of the Holy Prophet) commanded that a tent should be pitched for her. It was pitched accordingly. And some other wives of Allah's Apostle ( ﷺ) commanded that tents should be pitched for them too. And they were pitched. When the Messenger of Allah (may peace he upon him) offered the morning prayer, he looked and found (so many) tents. Thereupon he said: What is this virtue that these (ladies) have decided to acquire? He commanded his tent to be struck and abandoned i'tikaf in the month of Ramadan and postponed it to the first ten days of Shawwal. (Using translation from Muslim 1173a)   

رَسُولُ اللهِ ﷺ إِذَا أَرَادَ أَنْ يَعْتَكِفَ صَلَّى الْفَجْرَ ثُمَّ دَخَلَ مُعْتَكَفَهُ وَأَنَّهُ أَمَرَ بِخِبَائِهِ فَضُرِبَ أَرَادَ الِاعْتِكَافَ فِي الْعَشْرِ الْأَوَاخِرِ مِنْ رَمَضَانَ فَأَمَرَتْ زَيْنَبُ ؓ بِخِبَائِهَا فَضُرِبَ وَأَمَرَ غَيْرُهَا مِنْ أَزْوَاجِ النَّبِيِّ ﷺ بِخِبَاءٍ فَضُرِبَ فَلَمَّا صَلَّى الْفَجْرَ نَظَرَ فَإِذَا الْأَخْبِيَةُ فَقَالَ الْبِرَّ يُرِدْنَ؟ فَأَمَرَ بِخِبَائِهِ فَقُوِّضَ ثُمَّ تَرَكَ الِاعْتِكَافَ فِي شَهْرِ رَمَضَانَ حَتَّى اعْتَكَفَ فِي الْعَشْرِ الْأُوَلِ مِنْ شَوَّالٍ