What is the authenticity of the hadith "Pray the prayer of one who is bidding farewell," and what is the ruling on saying it?

Question:
The hadith: ?

Answer:
The hadith is acceptable. The hadith of al-'Arba' says: "He prayed with them." As for "Pray," I do not know its status. However, it says: "The Prophet (peace and blessings be upon him) prayed with them a great prayer," and it says: "It was as if it were the prayer of one who is bidding farewell," and he admonished them with an admonition as if it were the admonition of one who is bidding farewell. As for "Pray the prayer of one who is bidding farewell," I do not know its chain of narration. However, a believer should take care in every prayer, because he does not know whether he will pray after it or not. So he should take care and complete it.
Q: Does the imam say to the congregation: "Pray the prayer of one who is bidding farewell," and what does he say: "Straighten your rows"?
The Shaykh: I do not know a basis for it. He says what the Prophet (peace and blessings be upon him) said: "Be straight, be even, close the gaps, and draw near to one another." It is something new that I do not know. And what the Prophet (peace and blessings be upon him) did is sufficient.