Iman is in the heart and not about growing the beard
In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Al-Allamah Salih Al-Fawzan, may Allah preserve him, was asked: What do you say regarding the one who when it is said to him, “Fear Allaah regarding sins, such as shaving the beard, smoking and Isbaal [i.e. wearing one’s garments below the ankles]”, he says, “Iman is in the heart and not about growing the beard, abandoning smoking and Isbaal”. And he says, “Indeed, Allah does not look at your bodies, rather He looks at your hearts”.
Response: This statement is often uttered by some of the ignorant people or those who hold false and erroneous views. It is a statement of truth by way of which falsehood is intended because he utters this statement to justify his sins – that even in the absence of deeds that are to be performed in obedience to Allah as well as not abandoning forbidden deeds, Iman in the heart is sufficient. This false and erroneous view is clearly exposed because Iman is not only something in the heart; rather Iman – as defined by Ahlus Sunnah Wal Jamaa’ah – is speech of the tongue (i.e. acts of worship carried out with the tongue), belief in the heart and deeds of the limbs. Imam Al-Hasan Al-Basri, may Allah have mercy upon him, said, “Iman is neither merely to say something nor merely hope, rather it is what settles in the heart and deeds testify to it”.
Deeds of disobedience and abandoning obedience is proof that either there is no Iman in one’s heart or it is deficient. Allah [The Exalted] said: [يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُواْ لَا تَأۡڪُلُواْ ٱلرِّبَوٰٓا – O you who believe! Eat not Riba (usury)]. [Aal Imran. 130]
Allah said: [يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُواْ ٱتَّقُواْ ٱللَّهَ – O you who believe! Do your duty to Allah and fear Him]. [Al-Maa’idah. 35]
Allah said: [مَنۡ ءَامَنَ بِٱللَّهِ وَٱلۡيَوۡمِ ٱلۡأَخِرِ وَعَمِلَ صَـٰلِحً۬ا- whosoever believed in Allah and the Last Day and worked righteousness]. [Al-Ma’idah. 69]
Allah said: [إِنَّ ٱلَّذِينَ ءَامَنُواْ وَعَمِلُواْ ٱلصَّـٰلِحَـٰتِ – Truly those who believe, and do deeds of righteousness]. [Al-Baqarah. 277]
Allah said: [مَنۡ ءَامَنَ بِٱللَّهِ وَٱلۡيَوۡمِ ٱلۡأَخِرِ وَعَمِلَ صَـٰلِحً۬ا – whoever believes in Allah and the Last Day and do righteous good deeds]. [Al-Baqarah. 62]
Iman cannot be complete except when accompanied by righteous deeds and abandoning disobedience. Allah [The Exalted] said:
وَٱلۡعَصۡرِ
إِنَّ ٱلۡإِنسَـٰنَ لَفِى خُسۡرٍ
إِلَّا ٱلَّذِينَ ءَامَنُواْ وَعَمِلُواْ ٱلصَّـٰلِحَـٰتِ وَتَوَاصَوۡاْ بِٱلۡحَقِّ وَتَوَاصَوۡاْ بِٱلصَّبۡرِ
By Al-‘Asr (the time). Verily! Man is in loss; except those who believe [in Islamic Monotheism] and do righteous good deeds, and recommend one another to the truth, and recommend one another to patience (for the sufferings, harms, and injuries which one may encounter in Allah’s Cause during preaching His religion of Islamic Monotheism etc] [Surah Al-Asr]
Allah said: [يَـٰٓأَيُّہَا ٱلَّذِينَ ءَامَنُوٓاْ أَطِيعُواْ ٱللَّهَ وَأَطِيعُواْ ٱلرَّسُولَ – O you who believe! Obey Allah and obey the Messenger [Muhammad]. [An-Nisaa. 59]
Allah said: [يَـٰٓأَيُّہَا ٱلَّذِينَ ءَامَنُواْ ٱسۡتَجِيبُواْ لِلَّهِ وَلِلرَّسُولِ إِذَا دَعَاكُمۡ لِمَا يُحۡيِيڪُمۡۖ- O you who believe! Answer Allah (by obeying Him) and (His) Messenger when he calls you to that which will give you life [i.e. fill your hearts with Iman, guidance and lead you righteous deeds]. [Al-Anfaal. 24]
Belief in the heart alone is not enough without uttering one’s Iman with the tongue and performing deeds with the limbs because this [i.e. belief in the heart without performing deeds] is the Madhab of those Murji’ah amongst the Jahmiyyah and other than them, and it is a false Madhab; rather one has to believe in the heart, utter his Iman [i.e. what he believes in] and perform deeds with the limbs. Committing acts of disobedience is a proof of the weakness and deficiency of the Iman in one’s heart because one’s Iman increases when Allah is obeyed and decreases when Allah is disobeyed.
Al-Muntaqaa Min Fataawaa Ma’aal Ash-Shaikh Al-Allaamah Ad-Doctur Salih Al-Fawzan. 1/1920. Publisher Daar Al-Imaam Ahmad. 1st edition (2013)