Ibn Majah

Commentary:
(1)
Just as a lock cannot be opened without a key, in the same way, it is not possible to enter into prayer without being purified from minor impurity (hadath asghar) and major impurity (hadath akbar).
From this, it is understood that purification (taharah) is a condition for prayer.

(2)
With the takbir, that is, by saying "Allahu Akbar," all actions contrary to prayer become prohibited; therefore, the takbir recited at the time of entering prayer is called the "takbir tahrimah."
In this respect, its status in prayer is the same as that of donning the ihram in Hajj,
by which certain restrictions are imposed upon the pilgrim.

(3)
The restrictions imposed by the takbir tahrimah are lifted when the worshipper completes the prayer by turning the head for salam; for this reason, it is called "tahlil," meaning that those things which were forbidden and prohibited during prayer now become lawful and permissible.

(4)
The method of entering into prayer is only through the takbir; a person cannot enter prayer by uttering any other phrase or by mentioning Allah's name in any other language. The opinion of some scholars is not correct that prayer begins by mentioning Allah's name in any manner whatsoever—
whether one says "Allah A'zam" or "Allah Kabir," etc.

(5)
Some scholars are of the view that after completing the remaining acts of prayer, if the worshipper performs any act contrary to prayer instead of salam, the prayer is completed.
Whereas from this hadith it is understood that there is only one way to exit the prayer, and that is salam.
Related ahadith (Hadith: 914 to 917)
will be mentioned ahead.

1:
That is, by entering the prayer with the words “Allahu Akbar,” all those actions become prohibited which Allah has forbidden during prayer.
Entering the prayer by saying “Allahu Akbar” was the constant practice of the Prophet (sallallahu alayhi wa sallam).
Therefore, beginning the prayer with any other Arabic or non-Arabic word is not valid.

2:
That is, one can exit the prayer only by saying “as-salamu alaykum wa rahmatullah.”
It is not permissible to exit the prayer by any other word or action.

3:
These words are among the terms of commendation (ta'dil), and according to the majority, this term indicates the fourth level of a narrator’s commendation, in which the narrator’s uprightness is clear but his precision is not clear.
When Imam Bukhari (rahimahullah) calls someone “truthful” (saduq), he means “reliable” (thiqah), which is the third level of commendation.

4:
“Maqaarib al-hadith” is one of the ranks in the levels of memorization and commendation.
The word “maqaarib” is read in two ways:
With a fatha (zabar) on the letter ra,
and with a kasra (zer) on the letter ra.
With a fatha, “maqaarab al-hadith” means that the hadith of others is close to his hadith.
With a kasra, “maqaarib al-hadith” means that his hadith is closer to the hadith of other reliable narrators,
that is, there is no odd (shaadh) or rejected (munkar) narration in it.
Imam Tirmidhi (rahimahullah) has used this term regarding Walid ibn Rabah and Abdullah ibn Muhammad ibn Aqil.

Benefits and Issues:
➊ Ablution (wudu) is obligatory and a condition for prayer (salah). If ablution is nullified during the prayer, one must leave the prayer and perform ablution again.
➋ The prayer begins only with the utterance of "Allahu Akbar," and from that moment, speaking and other actions become prohibited; for this reason, it is called the "takbir of prohibition" (takbir tahrimah). The prayer ends with the salutation (salam), and thus this restriction also comes to an end.

618. Commentary:
By saying the takbir, i.e., «الله اكبر», ordinary activities become prohibited, and by saying «السلام عليكم», these activities become permissible. It is also established that the beginning of the prayer is with the word «الله اكبر», and to exit from it, «السلام عليكم ورحمةالله» is legislated, not any other words or actions.