Which of the following descriptions of the prayer row is more correct: leaving a space not exceeding a handspan between the worshipper's feet with the possibility of small gaps between feet, or is it necessary for feet to be touching even if the distance between the worshipper's feet exceeds a handspan? And does a distance between the feet exceeding a handspan invalidate the prayer? And do slight gaps affect the straightness of the row?

There is no necessary connection between joining the shoulders in the row and leaving a space between the feet. Rather, the Sunnah (definition) is to join shoulder to shoulder and foot to foot without exaggeration, based on the saying of Nu'man ibn Bashir: "I saw a man among us joining his ankle to his companion's ankle," and the action of the Companions in the hadith (definition) of Anas: "One of us would join his shoulder to his companion's shoulder and his foot to his foot," and the command of the Prophet, peace be upon him: "Straighten your rows, align your shoulders, fill the gaps, and do not leave openings for Satan." The prayer is not invalidated by increasing the distance between the feet of the worshipper himself.