Should she leave the prayer in congregation because her child cries?
Question

                I was praying in congregation in the mosque when my daughter started crying and they brought her to me from outside the mosque. She was crying loudly and I was forced to cut short my prayer.

 What is the ruling on what I did? Have I sinned? Please note that the women’s prayer-place is directly behind the men and there is nothing separating us but a barrier. If I had carried on praying, her crying would have disturbed the other worshippers.
Praise be to Allah.Firstly: 
The scholars 
    are agreed that stopping an obligatory prayer deliberately with no excuse 
    after having started it is haraam. 
The 
    legitimate excuses that make it permissible to stop the prayer include those 
    which are mentioned in the saheeh Sunnah, and those which have been 
    determined by analogy to be similar to them or to be stronger reasons. 
Among the 
    legitimate excuses that make it permissible to stop the prayer – whether it 
    is obligatory or naafil – are killing snakes, fear of losing one's 
    belongings, helping one who is in distress, saving one who is drowning, 
    putting out a fire, and warning a heedless person of something that may harm 
    him. 
These 
    excuses have been mentioned in the answers to question no. 
    65682 and 
    3878. 
Secondly: 
If a child 
    is crying and his father or mother are unable to quieten him down during a 
    congregational prayer, then it is permissible to stop praying in order to 
    quieten him down, for fear that his crying may be because of some harm that 
    has befallen him, and for fear that the prayer of others may be spoiled 
    because of the disturbance. 
If it is 
    possible to quieten him down with a slight movement and without turning away 
    from the qiblah, then the woman may do that and go back to her prayer. She 
    may, for example, move backwards to pick him up without stopping her prayer. 
    But if she is not able to quieten him down without stopping her prayer 
    altogether, then she should do that and there is no sin on her in sha 
    Allaah. 
It says in
    Mataalib Ooli al-Nuha (1/641): 
It is Sunnah 
    for the imam to make the prayer brief if something happens during the prayer 
    that means that one of the worshippers has to stop praying, such as hearing 
    a child crying, because the Prophet  (peace and blessings of Allaah be 
    upon him) said: “I start the prayer intending to make it long, then I hear a 
    child crying, so I make it brief lest I cause hardship to his mother.” 
    Narrated by Abu Dawood. End quote. 
The scholars 
    of the Standing Committee were asked: 
Is it 
    permissible to stop praying if the worshipper sees an animal coming towards 
    him such as a scorpion or other poisonous animal? Similarly, when praying in 
    al-Haram, is it permissible to stop praying so that he can follow his son or 
    daughter who is about to get separated from him and lost? 
They 
    replied: 
If it is 
    easy for him to get rid of the scorpion etc without stopping the prayer, 
    then he should not stop praying, otherwise he may stop. Similarly if it is 
    easy for him to look after his child without stopping the prayer, he should 
    do so, otherwise he may stop it. 
End quote. 
Shaykh ‘Abd 
    al-‘Azeez ibn ‘Abd-Allaah ibn Baaz, Shaykh ‘Abd al-Razzaaq ‘Afeefi, Shaykh 
    ‘Abd-Allaah ibn Ghadyaan. 
Fataawa 
    al-Lajnah al-Daa’imah li’l-Buhooth al-‘Ilmiyyah wa’l-Ifta’ 
    (8/36, 37) 
See also the  answer to question no. 26230. 
And Allaah knows best.