In the name of Allāh, Most Merciful, Bestower of Mercy.
Wābisah Ibn Maʿbad (radiyallāhu ‘anhu) narrated that Allāh’s Messenger (salallāhu ‘alaihi wasallam) said to him, “You have come to me asking about piety and sin? Wābisah said, “Yes.” So the Messenger of Allāh (salallāhu ‘alaihi wasallam) said, “Consult your heart and consult your soul.” He repeated it three times, and then said, “Piety is what brings tranquillity to the soul, and sin is that which causes uneasiness in the soul and hesitation in the heart, even after the people have given you the fatwā (verdict) for its allowance repeatedly.”
Many people misunderstand this hadīth and misuse it, thinking that what is lawful and unlawful is judged by their desires and whims, and when they are asked why they have made lawful what is unlawful, they answer, “I consulted my heart”! This hadīth is not a proof that allows a person to contradict the Revelation of Allāh, rather, it is directed to the person who has a good heart and has been told that such-and-such is halāl or harām but he feels uneasy in his heart, so he withholds due to this hadīth until the affair is made clear from the Book and Sunnah because the Revelation brings ease to the heart of the believer. Imām Ibn Al-Qayyim (rahimahullāh) said in Iʿlām Al-Muwaqqiʿīn,
“It is not permitted for a person to act solely on the basis of a fatwā of a muftī if his soul is not at ease with it, and while something waivers in his heart from accepting it and is hesitant concerning it. This is due to the saying of the Prophet (salallāhu ‘alaihi wasallam), ‘Consult your heart even if the people have given you a fatwā (verdict) concerning it repeatedly.’
So, it is obligatory upon him to first consult his soul, he does not dissociate the fatwā of the mufti from Allāh if he knows that the reality of the affair opposes the fatwa he has issued, just like the ruling of the judge (qādī) in his favour does not benefit him due to the saying of the Prophet (salallāhu ‘alaihi wasallam), ‘If I judge in someone’s favour with something from the right due to his brother, then let him not take it—otherwise, he has taken a portion of the fire.’
The muftī and qādī in this respect are the same. A person seeking a fatwā should not think that something is lawful for him solely on the basis of a fatwā in a fiqh issue about which he has asked when he knows the fatwā opposes the concealed reality of the said issue—this is regardless of any hesitation or uneasiness he feels in his chest so long as he knows the reality of what is concealed, or that he has doubt concerning it, or he is ignorant of it, or that he knows the muftī is ignorant of its reality, or he is biased in his fatwā, or that there is an absence of restricting himself (in his verdict) to the Book and Sunnah, or because he is well-known for issuing fatāwā that have deceit or allowances that oppose the Sunnah and so on from the reasons that prevent one from trusting his fatwā, and prevent the soul from being at ease with it.”
ʿAllāmah Ibn ‘Uthaimīn (rahimahullāh) said in explanation of the above hadīth of Wābisah (radiyallāhu ‘anhu), “Even if a muftī gives you a fatwā that something is permissible but your soul is not tranquil and is not at ease with it, then you should not act on the fatwā—and this is from goodness and piety unless you know that there is an illness in your soul emanating from whisperings, doubt and confusion—in that case, do not pay attention to that (and accept the fatwā). The Prophet (salallāhu ‘alaihi wasallam) was only addressing (in this hadīth) those people who do not have in their hearts an illness.”
As for the fatāwā of the scholars of Sunnah and Hadīth that are supported by the texts of the Qurān and Sunnah, and further substantiated by the positions of the Sahābah and early Salaf, then there is not a sound heart, obedient to Allāh, that would reject those rulings, and all praise is due to Allāh. As for the erroneous fatwā of a scholar that contradicts the Revelation, then it is not accepted, even if he is from the People of Sunnah and Hadīth―he is honoured, respected, and not reviled, but his fatwā is not to be followed. And we say that he is rewarded (one reward) for his ijtihād (striving to attain the truth) inshā’-Allāh; nevertheless, his fatwā is not acted upon.
Abu Khadeejah Abdul-Wāhid.
 Reported by Imām Ahmad (no. 17545, 4/227), Ad-Dārimī (2/246). Cited in Al-Arbaʿīn An-Nawawiyyah, and An-Nawawī graded it hasan, as did Al-Albānī; see Sahīh Al-Jamīʿ As-Saghīr (no. 948, 1/224) and Sahīh At-Targhīb (no. 1734).
 Iʿlām Al-Muwaqqiʿīn ʿan Rabbil-ʿĀlamīn, Dār Al-Kitāb Al-ʿArabī publishers, second edition, (4/225-226).
 Sharh Riyād As-Sālihīn (2/284).
Masha Allah very useful article, May Allah bless our ustadh, Ameen!
Jazakullahu khair, Allaah preserve you and bless you Ustadh. Aamen