Messenger of Allah ﷺ said, "Gabriel read the Qur'an to me in one way (i.e. dialect) and I continued asking him to read it in different ways till he read it in seven different ways." (Using translation from Bukhārī 3219)
"اقْرَأَنِى جِبْريلُ القرآن عَلَى حَرْفٍ، فَرَاجَعْتُهُ فَلَمْ أَزَلْ أستزيدهُ فيزيدُنى حتى انْتهى إلى سبعةٍ أحرفٍ ".