Benefits
First: Allah, Exalted is He, says, “O you who believe, guard yourselves and your families from a Fire whose fuel is people and stones” (Q 66:6).
The Messenger of Allah ﷺ said, “Each of you is a shepherd, and each of you will be questioned about his flock; a man is a shepherd in his household and will be questioned about his flock.”
Child custody has been legislated solely to nurture the child and to protect him from harm. The gravest harm that can befall him is the loss of his religion and his character. If the leading scholars have denied the tender-hearted mother any share in custody when she is a disbeliever—and if some of them do allow her a share, it is only under supervision—then, once you understand this, you will realise how lax many Muslims have become with their children when they place them in the care of housemaids brought from abroad, some of whom are non-Muslims, while those who are nominally Muslim are Muslims in name only. These innocent children, who absorb everything that is given to them and imitate everything done before them, grow up under such influence. Worse still are those who enrol their children in nurseries and kindergartens supervised by Christians or atheists; by doing so they commit a grave injustice against their offspring, and Allah Almighty will hold them accountable for this negligence and this dereliction with respect to their children.
Second: Shaykh Taqi al-Din said, “Whichever of the two parents we place first in the matter of custody, we do so only when the child’s welfare is achieved thereby or harm is averted thereby. If, however, harm is present with one of them, the other parent is without doubt more entitled.”
Shaykh ʿAbd al-Raḥmān al-Saʿdī said, “The correct view concerning custody is that the order mentioned by the jurists is to be followed so long as it secures the child’s benefit. If it does not, then the obligation is to pursue the child’s best interest. The entire topic indicates that the aim is to realise the ward’s welfare and repel his harm; whoever achieves that is more deserving than anyone else, even if…"