Al-Qushayri reported: ‘Amr ibn Abdi Qays, may Allah have mercy on him, said, “Were the veil over the Unseen to be lifted, that would not increase our conviction.”
Source: al-Risālah al-Qushayrīyah 1/319
عن القشيري قال عَامِرِ بْنِ عَبْدِ قَيْسٍ رحمه الله لَوْ كُشِفَ الْغِطَاءُ مَا ازْدَدْتُ يَقِينًا
1/319 الرسالة القشيرية