كَأَنَّمَا introduces a comparison, “as though.” يُسَوِّي is a present-tense verb meaning “he makes even,” and صُفُوفَنَا means “our rows,” with the attached نَا indicating “our.”
The image of straight arrow-shafts communicates the need to avoid unnecessary irregularity in the line. The fact that the Prophet ﷺ repeatedly corrected the rows explains how the community learned the practice. A straight row is a shared responsibility: the imam guides, while worshippers cooperate.