Is one who prays at night with Surat Al-Ikhlas considered among the "muqantarīn" (those who pray with a thousand verses), given that it is equivalent to one-third of the Quran, while the "muqantarīn" pray at night with a thousand verses?

It has been established that reciting Surat Al-Ikhlas is equivalent to one-third of the Quran, but this does not mean it suffices for reciting the entire Quran. One who recites Surat Al-Ikhlas obtains a great reward, but they would not have recited the entire Quran, because the Quran contains knowledge, rulings, and stories that are not found in Surat Al-Ikhlas.

Equating one thing with another does not imply that one thing suffices for the other. For example, reciting "La ilaha illa Allah wahdahu la sharika lah..." ten times is equivalent to freeing four slaves, but it does not suffice for freeing a slave as an expiation.

Therefore, one who recites Surat Al-Ikhlas three times is not considered as one who has recited the entire Quran, and its recitation does not suffice for Al-Fatiha in prayer.