Distance Between the Feet During Prayer
What should be the distance between the feet during the congregational prayer? How should we line up during prayer?
First of all, straightening the rows during congregational prayers is a must. Anas ibn Malik narrated that the Prophet (peace be upon him) said, “Straighten your rows for I see you from behind my back.” Anas added, “Every one of us used to put his shoulder with the shoulder of his companion and his foot with the foot of his companion.” (Al-Bukhari)
In another hadith, An-Nu`man ibn Bashir narrated that the Messenger of Allah (peace be upon him) paid attention to the people and said three times; straighten your rows (in prayer); by Allah, you must straighten your rows, or Allah will certainly put your faces in contrary directions. I then saw that every person stood in prayer keeping his shoulder close to that of the other, and his knee close to that of the other, and his ankle close to that of the other.” (Abu Dawud)
As for the distance between the feet, there is no text that was reported about its specification. This varies from one person to another. It may be appropriate to be moderate: one should not join them nor widely separate between them. He should just be in-between, naturally.
To get more information about the rulings of forming and straightening the row during prayer, please watch this short video with Dr. Muhammad Salah.
Source: Huda Youtube Channel.