We know that the holy quran reavealed on 7 systems of reading . we recieved that systems from the prophet (peace be upon him) by seven rawee(narrator).They are
1. Abdullah ibn kasir
2. nafe ibn abi naeem
3. abdullah ibn amer ash shamee
4. abu amr ibn a'la al basree
5. asem
6. hamjah
7. kasaee
We recieved the differents system of quran recieting from that honourable persons. they narrated that from their teachers they are from their teachers. in this way we recieved all this from the prophet muhammad (peace be upon him)