What is the first thing that should be done to strengthen faith when one feels it weakening?

Weakness of faith is a serious disease that leads to committing sins and slackening in duties. It cannot be overcome except by strengthening one's faith, and this is done by removing the causes that lead to its weakness. Some of these causes include: staying away from environments of faith, lacking righteous role models, associating with people of immorality and transgression, excessive preoccupation with worldly matters, family, and children, having prolonged hopes, and indulging excessively in permissible things.

A Muslim must remove these causes and work against them to strengthen his faith, for "faith increases with obedience and decreases with disobedience."

Among the best remedies for this condition is for the servant to shift his heart from this world to the Hereafter, and to turn his heart to the meanings of the Qur'an and ponder them, applying its verses to the ailment of his heart. This must be accompanied by supplication for steadfastness and the renewal of faith.