إِنَّ لِكُل عَمَلٍ شِرَّةً، وَلِكُل شِرَّةٍ فَتْرَةً ، فَمَنْ كَانَ فَتْرَتُهُ إِلَى سُنَّتِي فَقَدِ اهْتَدَىٰ، وَمَنْ كَانَتْ إِلَى غَيْرِ ذٰلِكَ فَقَدْ هَلَكَ

Every deed has its period of zeal and fervor, and every fervor has a period of cooling down. Whoevers’ cooling down period is on the sunnah, he is rightly guided, otherwise he is destroyed.

—The Prophet Muhammad (S)

[Hadith of Ibn Umar reported by Ibn Hibban and authenticated by al-Mundhiri, Ahmad Shakir, al-Albani and Shuaib al-Arnaut]