The Prophet ﷺ said,
“Behold, in your body there is a piece of flesh, when it becomes sound, the entire body becomes sound, and when it becomes bad, the entire body becomes bad. Behold, it is the heart.”
The basis is the heart and the limbs are the supporters and soldiers of the heart. The heart implements what it wants through them; however, if the limbs show some violations, can the person use as proof for the action that piety is in the heart? We say, if there was something hidden or piety was present in that heart, it would have appeared upon the limbs. The violations which appeared upon the limbs are proof for the false claim that it resulted from piety. When the companion used as proof the Words of Allaah ,
{لَيْسَ عَلَى ٱلَّذِينَ ءَامَنُوا۟ وَعَمِلُوا۟ ٱلصَّـٰلِحَـٰتِ جُنَاحٌۭ فِيمَا طَعِمُوٓا۟ إِذَا مَا ٱتَّقَوا}
“There is not upon those who believe and do righteousness [any] blame concerning what they have eaten [in the past] if they [now] fear Allaah…” (Al-Maa’idah, 93)
and said, ‘A person can drink wine and be pious!’ ‘Umar said, ‘Your backside has missed the hole! If you were pious, you would not have drunk wine!’ person who has signs of apparent sin corruption, such as shaving his beard, and drinking what he drinks publicly, wears his garments below his ankles, or has other violations, would say, ‘Piety is here in the heart!’ If he had piety, he would have never done those actions. His actions thus sowed his false claim. There is no point for those who are disobedient in public to say, ‘Piety is here in the heart!’ If they were truly pious, they would not have committed such disobedience.