Why did wealthy Romans and Greeks hire tutors for their sons?
Wealthy Romans and Greeks hired tutors to prepare their sons, who were legal heirs, so that when they finished their tutoring they could take their place as lords of all. Until then, the child differed nothing from a slave and had no more authority in the family, even though he was the blood heir.
Les explains that Paul is illustrating from Roman and Greek culture, not the Jewish background. Les teaches that wealthy Romans and Greeks would hire tutors, and the sole purpose of these tutors was to prepare that child, that legal son who was an heir. As long as he was a child, he differed nothing from a slave, even though he was lord of all and a blood heir of the father. Until he had finished his time of tutoring, he had no more authority in the family than a slave.