التَّصْدِيقُ بَاقٍ فِي الْقَلْبِ، وَالذُّهُولُ إِنَّمَا هُوَ عَنْ حُصُولِهِ
Assent continues in the heart; inattention concerns its conscious presence.
People sleep, work, and attend to other matters without rehearsing their beliefs every moment. This does not mean faith disappears and reappears repeatedly. Persistence of a conviction and active awareness of it are different states.
Analogy: Someone can know a mathematical principle without consciously thinking of it throughout a conversation. Failure to attend to an established conviction does not immediately extinguish it.