Abu Hurairah narrated that Allah’s messenger sallallahu alaihi wasalam said
“When the Imam says, ‘Sami Allahu liman hamida (Allah hears those who sent praises and thanks to him), you should say, ‘Allahumma Rabbana lakalhamd (O Allah! Our Lord! All the praises and thanks are for You) And if the saying of any one of you coincides with that of the angels, all his past sins will be forgiven. (Bukhari)
1. Let’s rush to gain more ajr by raising our head and reciting the words calmly
To stand up Calmly and erect straight
Prophet Muhammad sallalahu alaihi wasalamm said, “No person’s prayer is complete until he has said Takbir then made ruku’ then has said Allah listens to the one who praises Him until he is standing straight. (Abu Dawood) When he raised his head, he would stand straigt until every vertebrae returned to its place.” (Al Bukhari)
Lengthening this Standing and Obligation to be at ease in it
Prophet sallallahu alaihi wasalam used to make this standing about as long as his Ruku’. In fact, he would stand (for so long) sometimes that one would say, “He has forgotten (because of his standing for so long).
He used to instruct to be at ease in the standing. No one’s prayer is complete unless does that, and used to say: Allah, Mighty and Sublime, does not look at the prayer of the slave who does not make his backbone upright in between his bowings and prostrations.” (Ahmad)