“The Prophet (ﷺ) stated that: «Every heart has a cloud covering it, with the similitude of a cloud covering a shining moon. It suddenly becomes dark when the cloud covers, but its brightness returns once the cloud has passed.» (recorded by at-Tabarâni and graded reliable by al-Albâni)
In this hadith, the Prophet (ﷺ) presents an analogy. Our hearts are likened to the moon; just as the moon is sometimes covered by clouds that conceal its light, the heart is sometimes covered by clouds of sin that cover its light. At other times, the clouds go away, and the light shines again in the heart. The light increases when we strive to engage in acts that will increase our eemân.”