(1) Takbir-e-Ta rimah

In fact, Takbir-e-Ta rimah (also called Takbir-e-Aula) is one of the pre-conditions for Salah but it has also been included in the Farai because it is closely attached to the acts of Salah.

(Ghunya-tul-Mustamli, P253)

1. If the Muqtadi says the word ‘Allah’ of Takbir-e-Ta rimah with the Imam but utters the word ‘Akbar’ before the Imam utters the same word, his Salah will not be valid.

(‘Alamgiri, V1, P68)

2. If the Muqtadi finds the Imam in Ruku’ and bends instantly for Ruku’ uttering the Takbir, i.e. he finishes the Takbir after he had already bent down to such an extent that his hands would touch his knees if he stretched them, his Salah will not be valid. 

(KhulaGa-tul-Fatawa, V1, P83) 

(What he should do on such an occasion is to utter the Takbir-e-Ta rimah whilst standing erect and then do Ruku’uttering. If he manages to join the Imam in Ruku’ even for a moment, the Rak’at will be counted, but if the Imam stands up before he joins the Imam in Ruku’, the Rak’at will not be counted.)

3. If someone is unable to pronounce Takbir because of dumbness or loss of the faculty of speaking due to any other reason, he does not have to utter it; just making intention in heart is sufficient for him. 

(Tabyin-ul-Haqa-aiq,V1, P109)

4. If the word “Allah” is mispronounced as (Allah) or the word (Akbar) as (Akbar) or " (Akbar), the Salah will be invalid. If anyone deliberately utters any of these words despite understanding their Fasid (wrong) meaning, he will become a Kafir (disbeliever). 

(Durr-e-Mukhtar, Rad-dul-Muktar, V2, P177)

These days, in case of a big Jama’at, most of the Mukabbirs, voluntarily conveying the voice of Takbir to those offering Salah at the back side, are heard mispronouncing the word ‘Akbar’ as ‘Akbar’ due to the lack of religious knowledge. As a result of this mispronunciation, the Salah of such Mukabbirs as well as that of those offering (alah following their Takbirs becomes invalid. Therefore, one should refrain from uttering Takbir without learning necessary rulings.

5. If someone performs first Rak’at’s Ruku’ with the Imam, he will gain the Šawab of Takbir-e-Aula. 

(‘Alamgiri, V1, P69)