Shaykh Muhammad
ibn Saalih al-‘Uthaymeen (may Allaah have mercy on him) said:
Allaah has enjoined fasting upon every
Muslim who is accountable, able to do it & not traveling. As for young
children who have not yet reached the age of puberty, fasting is not obligatory
for them, because the Prophet (peace and blessings of Allaah be upon him) said:
“The pen has been lifted from three” & he mentioned young children until they
reach puberty. But the child’s guardian must tell him to fast if he
reaches an age where he is able to do so, because that comes under the heading
of training him to implement the pillars of Islam.
We see some people leaving their children alone & not telling them to pray or fast, but this is wrong, & he (the parent)
will be responsible for that before Allaah.
They say that they do not make their children fast out of kindness &
compassion towards them, but in fact the one who is truly kind &
compassionate towards his child is the one who trains him to acquire good
characteristics & to do righteous deeds, not the one who refrains from
disciplining and training him in a beneficial manner.
[Majmoo’ Fataawa
al-Shaykh Ibn ‘Uthaymeen, 19/19, 20]