يَا أَيُّهَا الَّذِينَ آمَنُوا لِمَ تَقُولُونَ مَا لَا تَفْعَلُونَ

‏O you who believe! Why do you say that
‏which you do not do? (As-Saff: 2)

Imām as-Sa’di (rahimahullāh) explains this verse,

“Whoever speaks (and disseminates guidance and) the truth, yet their actions are in opposition to it; they (and their actions) are repugnant and reprehensible. Whereas the praiseworthy outcome  is for the person whose outward state, inward state, his statements and his actions are in conformity with the truth.”

Fath ar-Rahīm al-Malik al-‘Allām fī ‘ilm al-‘Aqā’id wa at-Tawhīd wa al-Akhlāq wa al-Ahkhām al-Mustambita min al-Qur’ān – pg 213