Regarding the Hebrew Scriptures, part of the answer lies in an ancient tradition that was established by God, who said that the text should be copied.* For example, Jehovah instructed the kings of Israel to make their own copies of the written Law.
Ngokuqondene nemiBhalo YesiHebheru, ingxenye yempendulo itholakala esikweni lasendulo elasungulwa nguNkulunkulu owathi imibhalo kufanele ikopishwe. * Ngokwesibonelo, uJehova wayala amakhosi akwa-Israyeli ukuba azikopishele uMthetho.