Praise be to Allaah.
The things that make faith decrease are as
Ignorance of the names and attributes of Allaah makes a decrease
in faith inevitable, because if a man is lacking in knowledge of the
names and attributes of Allaah, he will be lacking in faith.
Neglecting to think about the signs of Allaah in the universe
and the signs of sharee’ah (i.e., verses of the Qur’aan and miracles
of the Prophet (peace and blessings
of Allaah be upon him), etc.). This causes a decrease in faith or at
the very least it causes it to stagnate and not grow.
Committing sins, because sin has a profound effect on the heart
and on faith. Hence the Prophet
(peace and blessings of Allaah be upon him) said: “The adulterer at
the time when he is committing adultery is not a believer.”
Neglecting to do acts of worship, because neglecting to do acts
of worship causes a decrease in faith. But if the act of worship is
obligatory and a person neglects it with no excuse, then he is to be
blamed and deserves punishment. If the act of worship is not obligatory,
or it is obligatory but a person does not do it for a valid reason,
then he is lacking but is not to be blamed. Hence the Prophet
(peace and blessings of Allaah be upon him) described women as lacking
in reason and in religion, and he explained their lacking in religion
as being because of the fact that when they menstruate, they do not
pray or fast. But they are not to be blamed for not praying or fasting
during their menstruation; rather they are commanded not to do these
things at that time. But because they miss out on doing some of the
things that men do, they are regarded as lacking in this regard.
Majmoo’ Fataawa wa Rasaa’il Fadeelat al-Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allaah have mercy on him), vol. 1. p. 57