The simple and explicit answer regarding not to delve into Mutashabihaat (ambiguous) is given in Quran itself, but some people still delve into it so I considered it necessary to give classical commentary on the ayah from leading Mufasir of Quran i.e. Imam Qurtubi (Rahimuhullah)! He is amongst the top most classical Mufasireen and scholars, Muslims uphold the magnificence and usefulness of his marvelous Tafsir work called “Jami ul Ahkaam ul Quran”
In it he explains the beautiful ayah of Quran which talks about It having both Plain and ambiguous verses.
Quran states: He it is Who has sent down to thee the Book: In it are verses basic or fundamental (of established meaning); they are the foundation of the Book: others are ambiguous. But those in whose hearts is perversity follow the part thereof that is ambiguous, seeking discord, and searching for its hidden meanings, but no one knows its hidden meanings except Allah. And those who are firmly grounded in knowledge say: “We believe in the Book; the whole of it is from our Lord:” and none will grasp the Message except men of understanding. (3:7)
The mainstream Ahlu Sunnah Wal Jama’ah always battled against the literalists i.e. Salafis by simply attributing the meanings of Mutashabihaat onto Allah Ta’la alone, for example Hands of Allah, foot, shin, laughter, His descent, His establishment etc… The true and actual meaning of these are known by none but Allah, however while explaining to ultra-curious laymen the best opinion is to interpret them into what suits Allah’s Majesty.
The Original Arabic Reference!
***Imam Qurtubi (rahimaullah) writes***
قوله تعالى: { فَيَتَّبِعُونَ مَا تَشَابَهَ مِنْهُ ٱبْتِغَاءَ ٱلْفِتْنَةِ وَٱبْتِغَاءَ تَأْوِيلِهِ } قال شيخنا أبو العباس رحمة الله عليه: متبِعو المتشابه لا يخلو أن يتبعوه ويجمعوه طلباً للتشكيك في القرآن وإضلالِ العوامّ، كما فعلته الزنادقة والقرامِطة الطاعنون في القرآن؛ أو طلباً لاعتقاد ظواهر المتشابه، كما فعلته المجسِّمة الذِين جمعوا ما في الكتاب والسنة مما ظاهره الجِسمية حتى ٱعتقدوا أن البارىء تعالى جسم مجسم وصورة مصوّرة ذات وجه وعين ويد وجنب ورجل وأصبع، تعالى الله عن ذلكٰ؛ أو يتبعوه على جهة إبداء تأويلاتها وإيضاح معانيها، أو كما فعل صبِيغ حين أكثر على عمر فيه السؤال. فهذه أربعة أقسام:
الأوّل: لا شك في كفرهم، وأن حكم الله فيهم القتل من غير ٱستتابة.
الثاني: الصحيح القول بتكفيرهم، إذ لا فرق بينهم وبين عباد الأصنام والصور، ويستتابون فإن تابوا وإلا قتلوا كما يفعل بمن ٱرتدّ.
الثالث: ٱختلفوا في جواز ذلك بناء على الخلاف في جواز تأويلها. وقد عرف أنّ مذهب السلف ترك التعرّض لتأويلها مع قطعهم بٱستحالة ظواهرها، فيقولون أمِرّوها كما جاءت. وذهب بعضهم إلى إبداء تأويلاتها وحملِها على ما يصح حمله في اللسان عليها من غير قطع بتعيين مجمل منها.
الرابع: الحكم فيه الأدب البليغ، كما فعله عمر بصبيغ
Translation: The Exalted said: {But those in whose hearts is perversity follow the part thereof that is ambiguous, seeking discord, and searching for its hidden meanings} Our Shaykh, Abul Abbas (Rahimuhullah) said: Furthermore, the followers of the ambiguous verses (mutashabih) are not free from: Following it and collecting it, seeking to raise doubts in the Qur’an and (seeking to) misguide the laymen as done by the Zanadiqah (deviants), the Qaramitah, and the refuters of the Quran. Or seeking to believe in the “Outward (Zawahir)” meanings of the mutashabih as done by the Mujasmiya (deluded ones who give physical traits to Allah), those who collected from the Quran and Sunnah whatever gave a physical meaning when taken literally (dhahir). To the extent that they believed that the Creator is a physical body and a fashioned form, possessing a face and other things: hand, eye, side and finger. Exalted is Allah from that, with the most Supreme Exaltation. Or they sought out these (mutashabih) with a view to manifest its interpretations and clarify its meanings. Or (they did) like Subaygh when he asked ‘Umar about them (the mutashabih) excessively.
So there are four categorical (verdicts) on them:
The First: There is no doubt about their disbelief (kufr) and that the judgment of Allah concerning them is execution without even asking them to repent.
The Second: The most sound (opinion) is to make takfīr on them (to consider them to be kafirs), since there is no difference between them and worshipers of idols and images. And they should be asked to repent. Thereafter, either they’ll repent, or if not, they should be executed as is done to an apostate (murtad).
The Third: There is a difference of opinion concerning that (action) based upon the difference of opinion in the permissibility of (various) interpretations. And it is known that the madhhab of the Salaf (pious predecessors) was to leave the undertaking of interpreting them while being certain that the literal meaning (Zawahir) was impossible. So they would say, “Let it pass as it came!” And some of them (the Salaf) took the madhhab of manifesting its interpretations by interpreting it with meanings consistent with the (Arabic) tongue without definitively confirming a specific possible meaning.
The Fourth: The judgment for him is to be taught a profound lesson as Amir ul Momineen Umar ibn al Khattab did to Subaygh [Tafsir ul Qurtubi i.e. Jami ul Ahkaam ul Quran under 3:7]
حدثنا عبد الله بن مسلمة حدثنا يزيد بن إبراهيم التستري عن ابن أبي مليكة عن القاسم بن محمد عن عائشة رضي الله عنها قالت
تلا رسول الله صلى الله عليه وسلم هذه الآية
هو الذي أنزل عليك الكتاب منه آيات محكمات هن أم الكتاب وأخر متشابهات فأما الذين في قلوبهم زيغ فيتبعون ما تشابه منه ابتغاء الفتنة وابتغاء تأويله وما يعلم تأويله إلا الله والراسخون في العلم يقولون آمنا به كل من عند ربنا وما يذكر إلا أولو الألباب
قالت قال رسول الله صلى الله عليه وسلم فإذا رأيت الذين يتبعون ما تشابه منه فأولئك الذين سمى الله فاحذروهم
Translation: Narrated Aisha: Allah’s Apostle recited the Verse: “It is He Who sent down upon you the Book, in which some verses have clear meaning, they are the substance of the Book, and others are those, in the meaning of which there is doubt. Those in whose hearts there is perversity pursue doubtful one desiring deviation and searching their own viewpoint of it, and its right interpretation is known to Allah alone. And those of firm knowledge say, ‘We believed in it, all is from our Lord and none accept admonition save men of understanding”. (3.7) Then Allah’s Apostle said, “If you see those who follow thereof that is not entirely clear, then they are those whom Allah has named [as having deviation (from the Truth)] ‘SO BEWARE OF THEM’. [Bukhari, Volume 6, Book 60, Number 70].