Ruling on the imam saying to the congregation, “Pray Pray like a man bidding farewell”

Firstly: 

It is Sunnah for the imam
to straighten the rows himself, or to tell the congregation to straighten
the rows. A variety of expressions are narrated in the Sunnah, all of them
telling the worshippers to straighten the rows, and warning them against
doing otherwise. Among the phrases that have been narrated are: “Straighten
the rows and stand close together” and “Straighten your rows, for
straightening the rows is part of establishing prayer” and “Straighten your
rows for straightening the rows is part of perfecting the prayer” and
“Straighten the rows in prayer for straightening the rows is part of doing
the prayer well” and “Stand straight and do not make the rows uneven, lest
that that create disharmony amongst you” and “Straighten the rows and stand
shoulder to shoulder and fill the gaps” – and other such phrases. 

There is no need to say any of these or other phrases if the
imam sees that the rows are straight. 

Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said: 

But if the imam turns round and sees that the rows are
straight and solid (with no gaps), and the people are standing in straight
rows, then it seems that he should not tell them to straighten the rows,
because that has been done – unless he intends thereby to tell them to keep
it like that – because these words have a meaning, they are not just words
that are to be said for no purpose. 

As’ilat al-baab il-Maftooh, no.
62. 

We do not know of any
phrase in the Sunnah with which the imam may encourage the worshippers to
focus more in their prayer and focus their hearts on Allaah and the prayer,
as if it were their last prayer and so on. If the imam always says that then
there is the fear that it may come under the heading of bid’ah (innovation).
There is nothing wrong with saying such things as a reminder but that should
be done sometimes, not all the time and in every prayer. 

We know of no basis for saying “Focus your hearts on Allaah”.
With regard to the phrase “Pray like a man bidding farewell,” there is a
saheeh report that the Prophet (peace and blessings of Allaah be upon
him) said this, but that was by way of general advice, not what the imam
should say before saying the first takbeer of the prayer. 

It was narrated that Abu
Ayyoob said: The Messenger of Allaah (peace and blessings of Allaah be
upon him) said: “When you stand to pray, pray like a man bidding farewell.
Do not say anything for which you will have to apologize. And give up hope
for what other people have.” 

Narrated by Ibn Maajah, 4171. Classed as saheeh by Shaykh
al-Albaani in al-Silsilah al-Saheehah, 401. 

And it was narrated that
Ibn ‘Umar said: The Messenger of Allaah (peace and blessings of Allaah
be upon him) said: “Pray like a man bidding farewell as if you can see Him,
for although you cannot see Him, He sees you, and do not be concerned about
what other people possess, then you will live a rich life. Beware of any
action that requires an apology.”

Narrated by al-Bayhaqi in Kitaab al-Zuhd (The Book of
Asceticism), 2/210. 

It is saheeh because of the existence of corroborating
reports, as Shaykh al-Albaani said in al-Silsilah al-Saheehah, 1914.