What is the proper manner of completing the rows in congregational prayer?

The virtue of congregational prayer

Congregational prayer holds great merit, being superior to individual prayer as stated in. Abu Saʿid al-Khudri (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) said, “Congregational prayer is superior to individual prayer by twenty-five degrees” (recorded in the Sahih of Bukhari). In another hadith, Abdullah Ibn ʿUmar (may Allah be pleased with them both) narrates that the Messenger of Allah (peace and blessings be upon him) said, “Congregational prayer is superior to individual prayer by twenty-seven degrees” (recorded by Bukhari).

Scholars have stated that congregational prayer is the hallmark of Islam. Abu Abdullah al-Mawwaq, the Maliki scholar, notes in Al-Taj wa Al-Iklil (2:396), “Ibn al-ʿArabi said, ‘Praying in congregation embodies the essence of the religion and is the hallmark of Islam.’” Moreover, the Shafiʿi scholar al-Dimyati notes in Iʿanat Al-Ṭalibin (2:13), “Congregational prayer is preferable, because it is more meritorious than individual prayer … and the hallmark of Islam is established through it.”

Manner of completing the rows in congregational prayer

The basic principle is that worshippers should stand in compact, complete rows without gaps. It is not permissible to start a new row until the preceding one is complete. Anas Ibn Malik (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) said, “Complete the front row, then the one following it; and whatever deficiency there is should be in the last row” (recorded by Abu Dawud in his Sunan). The implication of this ḥadith is that no new row should be formed until the preceding row has been completed. One should therefore begin by completing the first row, then the next, and continue in this manner until the last row. Al-Badr al-ʿAyni noted in his Commentary on Sunan Abu Dawud (3:220–221) that the Prophet’s words mean that no space should be left vacant in the first row whenever possible, and likewise in the second, third, and subsequent rows, until all are complete.

And Allah Almighty knows best.