Ubayy b. Ka'b said:The Prophet (ﷺ) was present at the pool of Banu Ghifar, Gabriel came to him and said: "Allah has commanded you to make your community read (the Qur'an) in one harf. He (the Prophet) said: 'I beg Allah His pardon and forgiveness; my community has not strength to do so'. He then came for the second time and told him the same thing till he reached up to seven harfs. Finally, he said: 'Allah has commanded you to make your community read (the Qur'an) in seven harfs; in whichever mode they read, that will be correct

English translation · Sunan Abu Dawud