This has been discussed and answered at length in Beliefs of Islam (عقائد الإسلام) and also in Proofs of the Mahdi Call (أدلة الدعوة المهدوية الشيعية).
In summary,
Even though every Proof of Allah or Divine Leader will experience miracles during their lives, the faith on any individual must always be subject to an element of doubt (لبس) and never be forced through being presented by an overpowering miracle (معجزة قاهرة).
Otherwise, we do not meet the objective of this life being an examination and a test – since the element of someone’s faith being tested would disappear if the unseen suddenly became visible to the naked eye.
The scenario of doubt (لبس) is present in the stories of people who spent time with any of God’s divine representatives, who will have experienced miracles in their company. It should be noted that others, who also witnessed the same miracles may have simply passed them off as some form of magic. An obvious example is that of Moses and the magicians, when his staff turned into a snake to defeat their magic: Pharaoh’s magicians had understood it to be anything but magic, but Pharaoh had thought of it as magic – “two instances of magic that have competed with each other" (سحران تظاهرا).
The scenario of an overpowering miracle (معجزة قاهرة) can be seen in the scenario of Pharaoh, where he finally accepted Moses’ message at the time of his death by drowning, when he had chased Moses and followed him into the Red Sea and even touched the water with his hand, as it stood around him.
Note: for a miracle to be overpowering, it is not necessary to touch the object within which the miracle is occurring, as Pharaoh did. The criterion is where no doubt can possibly occur, such that the observer must accept the miracle.
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(ولو جعلناه ملكا لجعلناه رجلا وللبسنا عليهم ما يلبسون) (الأنعام: ٩)
"Had we made him an angel, we would have made him a man and would have created doubt on them in the way that they doubt (The Cattle – 9)”
[Further analysis is given below]
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The information on this topic has been written in abundance, but we suffice with some passages from the Proofs of the Mahdi Shiite Call book below:
"The reason for entering into this world is for mankind to be subject to the examination and test. Allah said: “The One who created death and life to test you – which of you will be best in their work. And He is the Mighty, the Forgiving” (The Sovereignty: 2). So, if mankind entered the world to be subject to the examination, it is not correct for the Examiner who possesses ultimate wisdom to favour some above others, without reason, when entering this examination. It is also not correct to, without reason or any preamble on their part, invalidate the examination of some and to give them a higher result.
With regards the material, physical miracle: if there remained no element of doubt nor the potential for opponents to cast any suspicion, then this would result in an overpowering miracle, thus removing the element of the unseen, leaving no scope for belief in it (the unseen). It would invalidate the examination of some of those that are being examined and this in turn would result in some of them receiving preference without reason. It would nullify the examination of those that experienced the miracle – assuming it had taken place – since their faith would be purely materialistic and the proportion of the unseen would be zero. Those for whom the miracle had occurred would get preference over others and enter heaven without any examination, hence, there would be no justice amongst those who had entered the examination. To conclude: it is necessary for a miracle of a material nature – if it occurs- to be within the limits that do not contradict the divine tradition of belief in the unseen."
(p 156, Proof of the Mahdi Shiite Call)
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Original Arabic for the above passage
علة الدخول إلى هذا العالم هو الامتحان واختبار الناس. قال تعالى: (الذي خلق الموت والحياة ليبلوكم أيكم أحسن عملا. وهو العزيز الفغور)
(الملك-٢)
فإذا كان الناس دخلوا الدنيا للامتحان فلا يصح من الممتحن الحكيم المطلق تفضيل بعضهم على بعض في خوض هذا الامتحان دون سبب, ولا يصح إلغاء امتحان بعضهم وإعطائهم أفضل نتيجة دون سبب أو مقدمات قاموا بها.
والمعجزة المادية الجسمانية ‘إن لم يكن فيها إي مجال للبس وإلقاء الشبهة من المخالفين, فإنها ستكون قاهرة وتلغي مساحة الغيب, ولا تبقي للإيمان بالغيب فسحة, وتقوم بالإلغاء امتحان بعض الممتحنين, وفيها تفضيل لبعض الممتحنين دون سبب, فنجد أنها تلغي امتحان من تحصل له – على فرض حصولها – حيث إن إيمانه يكون إيمانا ماديا محضا ونسبة الغيب فيه صفرا, ونجد أن من تحصل معه قد فضل على غيره وحصل على الجنة دون امتحان, وبالتالي لم تحقق العدالة بين الداخلين في الامتحان, ولهذا فنحن نقول التالي: لا بد أن تكون المعجزة المادية – إن أتت – ضمن حدود لا تنقض السنة الإلهية للإيمان بالغيب.
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References:
أدلة الدعوة المهدوية الشيعية
https://ansars.at/wp-content/uploads/2020/10/Adillah_dawah.pdf
عقائد الإسلام
https://ansars.at/wp-content/uploads/2020/09/Aqaidulislam.pdf
إضائات من دعوات المرسلين
https://ansars.at/wp-content/uploads/2020/10/Ida2at-1-2-3.pdf