Imam Junayd al-Salik, Allah sanctify his secret, said:
“A sincere person changes forty times a day while the hypocritical show-off stays as he is for forty years.”
Imam al-Nawawi, explains:
“The meaning of this is that the sincere person moves with what is right, wherever it may lead, such that when prayer is deemed better by the Sacred Law, then he prays, and when it is best to be sitting with the learned, or the righteous, or guests, or his children, or taking care of something a Muslim needs, or mending a broken heart, or whatever else it may be, then he does it, leaving aside what he usually does.
And likewise for fasting, reciting the Qur’an, invoking Allah, eating or drinking, being serious or joking, enjoying the good life or engaging in self-sacrifice, and so on.
Whenever he sees what is preferred by the Sacred Law under the circumstances, he does it and is not bound by a particular habit or kind of devotion as the show-off is. “
(Recorded in the Majmu`Sharh al-Muhadhdhab)