Bukhari

Hadith Commentary:

The word "Ameen" is itself a supplication. Saying it aloud at the end of Surah Al-Fatihah in audible (jahri) prayers is a Sunnah of the Prophet (sallallahu alayhi wa sallam), upon which the three Imams—Imam Malik, Imam Shafi'i, and Imam Ahmad ibn Hanbal (rahimahullah)—acted. However, the Hanafis are deprived of this. They should reflect upon "wa laa tukhafit biha" and adopt a middle path.

Hadith Commentary:
(1)
It is narrated from Ibn Abbas radi Allahu anhu that the aforementioned verse was revealed concerning prayer (salah).
Allah, the Exalted, said to the Messenger of Allah sallallahu alayhi wa sallam:
Do not recite the Qur’an in prayer so loudly that the polytheists may revile the Qur’an, nor recite so quietly that even your companions cannot hear you; rather, adopt a middle course.
(Sahih al-Bukhari, al-Tafsir, Hadith: 4722)
Whereas Aisha radi Allahu anha said that this verse was revealed regarding supplication (du‘a).
Hafiz Ibn Hajar rahimahullah writes:
It is possible that Aisha radi Allahu anha was referring to supplication during prayer, thus both statements can be reconciled in this way.
(Fath al-Bari: 8/515)
(2)
Imam Bukhari rahimahullah established the chapter heading based on this reconciliation. Accordingly, Hafiz Ibn Hajar rahimahullah, citing Ibn Marduyah, has mentioned the reason for the revelation (shan al-nuzul) of this verse: When the Messenger of Allah sallallahu alayhi wa sallam would pray near the Ka‘bah, he would supplicate in a loud voice, and at that time this verse was revealed.
(Fath al-Bari: 8/515)

Hadith Footnote:

Benefits and Issues:
➊ The deeds of the day are presented at the beginning of the night, when the night envelops it.
➋ The deeds of the night are presented at the beginning of the day, before the day fully rises.
➌ Therefore, there is no contradiction between the two hadiths.