Tirmidhi

English Commentary:
1:
That is, in the verse of Surah At-Tawbah, the Divine statement ﴿لَمَسْجِدٌ أُسِّسَ عَلَى التَّقْوَى مِنْ أَوَّلِ يَوْمٍ﴾ — which mosque is intended by this?

2:
This hadith does not only indicate that by ﴿لَمَسْجِدٌ أُسِّسَ عَلَى التَّقْوَى﴾ is meant only the Prophet’s Mosque (Masjid Nabawi),
rather, the purpose of the Prophet sallallahu alayhi wa sallam was that this Masjid Nabawi too is founded upon piety (taqwa).
People have taken this meaning because, from the context and sequence in the Qur’an, it is clearly evident that this Divine statement refers to Masjid Quba.

698. Commentary: According to the scholars of Tafsir, «لَمَسْجِدٌ أُسِّسَ عَلَى التَّقْوَى» [التوبة 108 : 9] refers to Masjid Quba, because this is more in accordance with the circumstances of revelation. However, according to this hadith, it refers to Masjid Nabawi. In reality, both mosques are included in the meaning of these words, because the foundations of both mosques were laid by the Messenger of Allah (sallallahu alayhi wa sallam), and it is evident that the foundation of both must necessarily be upon piety (taqwa). However, since the remaining construction of Masjid Nabawi was also completed by him, and the rest of his life was spent in this mosque, and this mosque was blessed by his days and nights, therefore, this mosque is more deserving to be considered its referent. Nevertheless, Masjid Quba would also, after a week, be honored by his visit and by the blessing of his footsteps for a short while, so there is abundant good in it as well. That is why there is always a crowd of worshippers there too, although it cannot be compared to Masjid Nabawi.

Explanation:
1:
This statement refers to the verse of Allah, ﴿لَّمَسْجِدٌ أُسِّسَ عَلَى التَّقْوَى مِنْ أَوَّلِ يَوْمٍ﴾ (At-Tawbah: 108).

2:
There is a difference of opinion regarding which mosque is meant here: whether it is Al-Masjid an-Nabawi or Masjid Quba. In this hadith, it is mentioned that it is Al-Masjid an-Nabawi, while in another hadith it is stated that it is Masjid Quba. From the context and sequence of the verse, it is also clear that it refers to Masjid Quba. So, what is the answer to the statement of the Messenger of Allah (sallallahu alayhi wa sallam) in this hadith, "It is this mosque of mine"? The answer is that the meaning of your (sallallahu alayhi wa sallam) response is simply that the foundation of my mosque was also laid upon piety (taqwa) from the very first day. This is the summary of the explanations given by the scholars.