The Prophet (peace and blessings be upon him) said:
"You must certainly straighten your rows, or else Allah will certainly put discord between your faces."
Hadith Referenceصحیح الجامع الصغیر / حرف اللام / 5072
Hadith Gradingالألبانی:صحيح
Hadith Takhrij[ن] عن النعمان بن بشير. صحيح أبي داود ٦٦٩.