Praise be to Allah.
With regard to the format of takbeer: “Allaahu akbar, Allaahu akbar, Allahu akbar laa ilaaha ill-Allaah, wa Allaahu akbar, Allaah akbar, wa Lillaah il-hamd (Allaah is Most Great, Allaah is most Great, Allah is most Great there is no god but Allaah, Allaah is Most great, Allaah is most great, and to Allaah be praise),” this is proven from Ibn Mas‘ood (may Allah be pleased with him) and others of the early generation, whether the first takbeer is said twice or three times.
See al-Musannaf by Abu Shaybah, 2/165-168; Irwa’ al-Ghaleel, 3/125
With regard to the format of takbeer, “Allaahu akbaru kabeera wa alhamdu Lillaahi katheera wa subhaan Allaahi bukratan wa aseela… (There is no god but Allaah, Allaah is most Great, Allaah is most Great, much praise be to Allaah and glory be to Allaah at the beginning and end of the day…),” Imam al-Shaafa‘i (may Allah have mercy on him) said:
If he adds to that and says: “Allaahu akbaru kabeera wa alhamdu Lillaahi katheera wa subhaan Allaahi bukratan wa aseela, Allahu akbar wa la na‘budu illa Allah mukhliseena lahu al-deena wa law kariha al-kaafiroon, la ilaaha ill-Allah wahdah, sadaqa wa‘dah wa nasara ‘abdah wa hazama al-ahzaaba wahdah, laa ilaaha ill-Allah wa Allahu akbar (Allaah is most Great, much praise be to Allaah and glory be to Allaah at the beginning and end of the day. Allah is most Great and we worship none but Allah, and we make our worship purely for Him (alone) however much the disbelievers may hate that. There is no god but Allah alone; He fulfilled His promise and granted victory to His slave and defeated the Confederates alone. There is no God but Allah and Allah is most Great),” then he has done well. End quote.
Abu Ishaaq al-Shiraazi said in al-Muhadhdhab (1/121):
Because the Prophet (blessings and peace of Allah be upon him) said that atop al-Safa. End quote.
The matter is broad in scope, because the command is to say takbeer in general, and the Messenger (blessings and peace of Allah be upon him) did not single out any particular format of takbeeraat. Allah, may He be exalted, says (interpretation of the meaning):
“and that you must magnify Allâh [i.e. to say Takbîr (Allâhu-Akbar; Allâh is the Most Great) for having guided you”
So one may follow the Sunnah by saying any format.
Al-San‘aani (may Allah have mercy on him) said: In al-Sharh there are many formats narrated from a number of imams, which indicates that the matter is broad in scope and the general wording of the verse indicates that. End quote.
Subul al-Salaam, 2/72
Ibn Habeeb said: The dearest to me is to say: Allahu akbar, Allahu akbar, la ilaaha ill-Allah wa Allahu akbar, wa Lillahi al-hamd ‘ala ma hadaana, Allahumma aj‘alna laka min al-shaakireen (Allah is most Great, Allah is most Great, there is no god but Allah and Allah is most Great; praise be to Allah for having guided us; O Allah, make us among those who give thanks to You).
The format preferred by Yazeed was: “Allaahu akbaru kabeera wa alhamdu Lillaahi katheera wa subhaan Allaahi bukratan wa aseela, wa la hawla wa la quwwata illa Billaah (Allaah is most great, much praise be to Allaah and glory be to Allaah at the beginning and end of the day, and there is no power and no strength except with Allah).” And he said: Whatever you add or subtract, or whatever else you say, there is nothing wrong with it. End quote.
‘Aqd al-Jawaahir al-Thameenah, 3/242
Sahnoon said: I said to Ibn al-Qaasim: Did Maalik mention any particular takbeer to you? He said: No. He said: Maalik did not say anything specific concerning these matters. End quote.
Imam Ahmad said: It is broad in scope. Ibn al-‘Arabi said: Our scholars favoured the view that takbeer is general in scope, which is the apparent meaning of the Qur’aan, and I am inclined to favour this view.
al-Jaami‘ li Ahkaam al-Qur’aan, 2/307
Forms of takbeer for the two Eids that are proven from the salaf:
“Allahu akbar, Allahu akbar, Allahu akbar wa Lillahi al-hamd, Allahu akbar wa ajall, Allahu akbar ‘ala ma hadaana (Allah is most Great, Allah is most Great, Allah is most Great and to Allah be praise; Allah is most Great and most Glorious, Allah is most Great,as He has guided us).”
Narrated by al-Bayhaqi, 3/315, from Ibn ‘Abbaas (may Allah be pleased with him); classed as saheeh by al-Albaani in Irwa’ al-Ghaleel, 3/126
Ibn Hajar said: With regard to the format of the takbeer, the most saheeh that has been narrated concerning it is that which was narrated by ‘Abd al-Razzaaq with a saheeh isnaad from Salmaan who said: “Proclaim Allah’s greatness: Allahu akbar, Allahu akbar, Allahu akbaru kabeeran.
Fath al-Baari, 2/462
Adhering to what was narrated from the Sahaabah concerning that is more appropriate.
And Allah knows best.
See also the answer to question no. 36442.