Al-Nu’man b. Bashir said:the prophet (ﷺ) used to straighten us in the rows of prayer as the arrow is straightened, until he thought that we had learned it from him and understood it. One day he turned towards us, and shoulders in order, and say; Do not be irregular. And he would say: Allah and his Angels bless those who near the first rows

English translation · Sunan Abu Dawud