Ibrahim's Emigration, the Test of the Sacrifice of Isma`il, and how Allah blessed Him

Allah tells us that after He helped His close friend Ibrahim, peace be upon him, against his people, and after Ibrahim gave up hoping that they would ever believe despite all the mighty signs that they had witnessed, he emigrated away from them, and said:

وَقَالَ إِنِّى ذَاهِبٌ إِلَى رَبِّى سَيَهْدِينِ - رَبِّ هَبْ لِى مِنَ الصَّـلِحِينِ

In verse 102, it was said: فَلَمَّا بَلَغَ مَعَهُ السَّعْيَ قَالَ يَا بُنَيَّ إِنِّي أَرَ‌ىٰ فِي الْمَنَامِ أَنِّي أَذْبَحُكَ (Thereafter, when he reached an age in which he could work with him, he said, "0 my little son, I have seen in a dream that I am slaughtering you, so consider, what do you think?" ). From some narrations, it appears that this dream was shown to Sayyidna Ibrahim (علیہ السلام) for three consecutive days (Qurtubi). Then, it already stands settled that the dream of blessed prophets is a revelation (wahy). Therefore, this dream meant that Allah Ta'ala was asking Sayyidna Ibrahim (علیہ السلام) to slaughter his firstborn son. For that matter, this command could have been revealed directly through an angel. But, the wisdom behind communicating it through a dream was to unravel the obedience of Sayyidna Ibrahim (علیہ السلام) at its most sublime form. A command given through a dream could have a lot of room for interpretations and excuses by the human self. But, this was Sayyidna Ibrahim (علیہ السلام) . He did not take to the way of excuses. On the contrary, he simply bowed down (sans interpretations, sans hesitations) before the command of his Lord. (Tafsir Kabir)

In addition to that, the purpose of the great Creator here was neither to have Sayyidna Ismail (علیہ السلام) be slaughtered actually, nor was it to make it binding upon Sayyidna Ibrahim (علیہ السلام) that he slaughters him ultimately, instead, the purpose was to give the command that he should, on his part, do everything necessary to slaughter him and take all steps leading to his slaughter. Now, had this command been given to him verbally, it would disclose that the actual slaughter is not intended, and the element of test would have remained missing. Therefore, he was shown in a dream that he was slaughtering his son. From this Sayyidna Ibrahim (علیہ السلام) understood that what he was been commanded with is slaughter - and he was all set for it literally and comprehensively. Thus, the element of trial went the full circle, and the dream also came true. So, as said earlier, if this thing were to come through a verbal command, either there would have been no test, or the command would have to be abrogated afterwards.