What is spiritual languor in the life of a believer, and how does a believer's period of languor relate to the Sunnah of the beloved Chosen One, peace and blessings be upon him, with illustrative examples?

Lethargy is idleness concerning some supererogatory acts, such as night prayers, supererogatory fasting, and avoiding dubious matters. However, lethargy must not lead to violating the Sharia by abandoning obligatory duties or committing forbidden acts. Al-Manawi said in his commentary on the hadith, "Whoever's lethargy leads to my Sunnah, then he has been guided," meaning: my prescribed way.