Reference: Siyar A’laam an-Nubalaa – v14, p534
The truthful person [is one who] restricts his speech, food, sleep, and mixing with others [to only that which is necessary].
And [instead], he exerts himself in adhering to a routine engaged in worship, humility, the remembrance of death, and the uttering of:
«لَا حَوْلَ وَ لَا قُوٌَةَ إِلٌَا بِاللٌَهِ»
«there is no might nor power except with Allaah»