It is narrated from Sayyiduna Abu Malik Ash'ari (may Allah be pleased with him) that the recitation and standing in all four rak'ahs of the Messenger of Allah (peace and blessings be upon him and his family) were equal, except that he would prolong the first rak'ah so that people could arrive. The Prophet (peace and blessings be upon him and his family) would make the men stand in front of the children, the children behind them, and the women behind the children. Whenever he (peace and blessings be upon him and his family) performed sajdah and rose from it, he would say takbeer. Similarly, when after two rak'ahs he sat for tashahhud and then stood up for the third rak'ah, he would say Allahu Akbar.
Hadith Referenceالفتح الربانی / أبواب صفة الصلاة / 1667
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«اسناده حسن۔ أخرجه الطبراني في الكبير : 3436، وأخرجه ابوداود بذكر صف الرجال والغلمان فقط: 677 ، (انظر مسند أحمد ترقيم الرسالة: 22896، 22911 ترقیم بيت الأفكار الدولية: 23299»
Brief Explanation
Benefits: … The length of the rak‘ahs performed by the Prophet sallallahu alayhi wa sallam also varied from the aforementioned quantity. For example, the first two rak‘ahs of Zuhr (noon prayer) would be equal to thirty verses each, and the last two rak‘ahs would be equal to fifteen verses each. Similarly, the first two rak‘ahs of ‘Asr (afternoon prayer) would be equal to the last two rak‘ahs of Zuhr, and its last two rak‘ahs would be equal to half of that. This difference was also observed in the audible (jahri) prayers.