What does “Refresh your faith with There is no deity but God” mean?

Man needs to renew, to refresh, his faith because both he and his personal world are being continually renewed. An individual acquires or is transformed into a different individuality every year or every month, or even every day or every hour. Being subject to the passage of time, he puts on, like a model, the form of individuality every day.

As man himself undergoes such changes and renewals, so too, the transient world he inhabits passes and is replaced by a new one: every day a new world opens its doors to man.

Faith is the light of the life of each and every individuality which a man acquires during his lifetime, and it is also the light of each of the worlds that he inhabits. As for the formula, There is no deity but God, it is the key with which to obtain that light.

Also, man is constantly under the influence of his carnal self, his fancies and desires which, together with Satan, resort, enabled by the man’s own heedlessness, to many devices to injure his faith and cut off its light through evil doubts and suggestions. Furthermore, since it is contrary to Shari‘a (and, according to some leading scholars, indicative of unbelief) to leave go of certain words and actions, it is wise for a believer to refresh his faith again and again, every day, even every hour.

1. Haythami, Majma‘ al-Zawa’id, 1:52.