Imaam Abu Muhammad Al-Hasan b. `Alee b. Khalaf al-Barbahaaree (died 329H, rahimahullaah) stated in his Sharhus-Sunnah (point 43):
ومن زعم أنه يرى ربه في دار الدنيا فهو كافر بالله عز وجل
“And whoever claims that he saw his Lord in this world is a disbeliever in Allah, the Mighty and Majestic.”
Explanation of Shaikh al-Fawzaan:
It-haaf al-Qaaree of Shaikh al-Fawzaan vol. 1, p. 286 onwards):
Whoever claims that he saw Allah in this world with his own eyes, not in a dream, then such a person is a disbeliever. That is because Allah, the Mighty and Majestic, cannot be seen in this world. When the Kaleemullaah (The one to whom Allaah spoke directly), i.e. Moosaa (`alaihis-salaam) said:
قَالَ رَبِّ أَرِنِي أَنظُرْ إِلَيْكَ ۚ قَالَ لَن تَرَانِي وَلَٰكِنِ انظُرْ إِلَى الْجَبَلِ فَإِنِ اسْتَقَرَّ مَكَانَهُ فَسَوْفَ تَرَانِي
لَمَّا تَجَلَّىٰ رَبُّهُ لِلْجَبَلِ جَعَلَهُ دَكًّا وَخَرَّ مُوسَىٰ صَعِقًا
“And when Musa (Moses) came at the time and place appointed by Us, and his Lord spoke to him, he said: “O my Lord! Show me (Yourself), that I may look upon You.” Allah said: “You cannot see Me, but look upon the mountain if it stands still in its place then you shall see Me.” So when his Lord appeared to the mountain, He made it collapse to dust, and Musa (Moses) fell down unconscious. Then when he recovered his senses he said: “Glory be to You, I turn to You in repentance and I am the first of the believers.””
So no one will see Allah in this world, and this is something agreed upon by consensus amongst the Scholars. The seeing of Allah takes place in the Hereafter, because whilst the people are in this world they are weak and not able to see their Lord, the Mighty and Majestic, due to that weakness. For this reason when Allah showed Himself to the mountain, He made it collapse and it turned to dust, so what would be the case with the son of Aadam?! A human being that is made up of meat and blood. However, in the Hereafter, Allah will give the believers strength and they will be able to see Allah, and rejoice in seeing Him, the Most Perfect, the Most High. The seeing of Allah in the Hereafter by the believers is established and reported in Mutawaatir form (numerous narrators at every level of the chain of narration that it is not possible for them to have concocted a lie). As for the the life of this world, then it is not possible for any person to see Allah with his physical eyes.
Then there occurs some differing:
Did the Prophet (ﷺ) see Allah, the Most High, on the Night Journey through the Heavens (Mi`raaj) or not? That which is correct and that which most of the Scholars are upon is that the Messenger (ﷺ) did not see him with his eyes. Rather he saw Allah with his heart as no one can see him in this life – Allah is too magnificently great that He be seen in this worldly life. For this reason, when the Prophet (ﷺ) was asked, “Did you see your Lord on the Night Journey?” He replied:
“It is light that I saw.”
Reported by Muslim (no. 178) from Abu Dhar (radiyallaahu `anhu).
And he also said:
“His veil is light, and had He uncovered it, the sublimity of His countenance would have burnt all that His sight reached of His creation.”
Reported by Muslim (no. 179) from Abu Moosaa (radiyallaahu `anhu).