Praying before the Adhān has been called

Question:

O Shaykh Hassan, may Allah bless you and in your knowledge.

The questioner says:

He assumed the time of Asr had entered so he stood and prayed, however whilst he was praying he then heard the Adhan.

Is his prayer correct?
Or is it upon him to repeat the prayer?

May Allah reward you with good.

Answer:

It is incorrect and it’s upon him to repeat it.

Answered by:
Shaykh Abu Hamza Hassan bin Muhammed Ba Shu’ayb – may Allah preserve him –

Source:
https://t.me/Bashuaib/5545

Translated by:
Umm Habiba bint Nasir