Is praying behind the rows forbidden and does it invalidate the prayer?

Question : But is praying behind the rows forbidden such that it invalidates the prayer, or not?

Answer : The answer is that the majority of scholars hold that it is not forbidden and does not invalidate the prayer. Among them are the three Imams: Malik, Abu Hanifah, and al-Shafi'i, who hold that praying behind the rows, even without an excuse, does not invalidate the prayer. Yes. They say that this man prayed with his imam, following him. They say that the fact that he lagged behind the row does not invalidate his prayer, because he performed its pillars and conditions and followed the imam, and nothing remained for him except that he lagged behind the row. So where is the connection?
And the school of Imam Ahmad is that praying behind the rows is forbidden and invalidates the prayer. He cited as evidence for this the saying of the Prophet (peace and blessings be upon him) . He saw a man praying alone behind the rows and ordered him to repeat the prayer. So what is the answer?
The truth is, I cannot command you, my brothers. Regarding the prayer, this hadith states: "There is no prayer for one who prays alone behind the rows." It is not a case of forgetfulness, and he was ordered to repeat the prayer. And there is no repetition except for an invalid prayer, is there not? Yes.
If his prayer had been valid, the Messenger (peace and blessings be upon him) would not have required him to pray a second time, because Allah does not accept in prayer except once.
Those who said that it is not forbidden and does not invalidate the prayer, and they are the majority, say that the saying of the Prophet (peace and blessings be upon him), "There is no prayer for one who prays alone," is a negation of perfection, not a negation of validity. Just as in his saying, "There is no prayer in the presence of food." If a person prays in the presence of food, is his prayer invalid or valid? Valid. So they say "There is no prayer for the one who is behind," like "There is no prayer in the presence of food." A negation of what? In the name of Allah.