Takbīr during the Two ʿEids
(Summarised from the words of Shaykh al-Islām Ibn Taymiyyah)
Its timing.
The soundest view—adopted by the great majority of early and later scholars and by the leading jurists—is to begin the takbīr at dawn on the Day of ʿArafah and continue until the end of the Days of Tashrīq, reciting it after every obligatory prayer and when setting out for the ʿEid prayer. The four Imams are unanimously agreed on this.
Its formula.
The wording of the takbīr narrated from most Companions, and traced back to the Prophet ﷺ, is:
“Allāhu akbar, Allāhu akbar, lā ilāha illā Allāh;
Allāhu akbar, Allāhu akbar, wa lillāhi-l-ḥamd.”
Some jurists limit it to three repetitions of “Allāhu akbar” only. Others recite it three times and add:
“Lā ilāha illā Allāh, waḥdahu lā sharīka lah; lahu-l-mulk, wa lahu-l-ḥamd, wa huwa ʿalā kulli shayʾin qadīr,”
a wording related from Ibn ʿUmar. Abū Ḥanīfah, Aḥmad, and others preferred the first version. Some people recite it three times the first round and twice the second, a practice followed by a group of worshippers.
Our guiding principle here—one of the soundest principles—is that every form of worship, whether verbal or physical, that is supported by a reliable report is permissible and legislated; none of its variants is disapproved. The same applies to the different formats of the prayer of fear, the two forms of the adhān, the two forms of the iqāmah (paired or single phrases), the various formulas of the tashahhud, the opening supplications, the forms of seeking refuge, the additional ʿEid takbīrs, the different funeral-prayer formats, the qunūt after or before bowing, and so on. It is obvious that a legally responsible person cannot perform all these variants in the same moment, and combining them within a single act of worship is an innovation. Likewise, patching their wordings together is not prescribed. The correct practice is to alternate among them—following the Prophet ﷺ and reviving all his Sunnahs—performing this version on one occasion and that version on another. This unites the hearts of the ummah, revives the Sunnah, and realises obedience to him ﷺ.
Takbīr on momentous occasions
Ibn Taymiyyah said: Since the Sunnah has prescribed takbīr on ʿĪd al-Naḥr—in its prayer and sermon, after the prayers, while stoning the jamarāt, upon completing the fast, and at the time of offering the sacrifice—then when the Prophet ﷺ approached Khaybar he declared: “Allāhu akbar, Khaybar has fallen!”