Whether knowledge of all Holy Writ is required?

Objections

Objection 1 : It would seem that knowledge of all Holy Writ is required. For one from whose lips we seek the law, should have knowledge of the law. Now the laity seek the law at the mouth of the priest (Malachi 2:7). Therefore he should have knowledge of the whole law.
Objection 2 : Further, "being always ready to satisfy everyone that asketh you a reason of that faith and hope in you [*Vulg.: 'Of that hope which is in you; St. Thomas apparently took his reading from Bede]." Now to give a reason for things pertaining to faith and hope belongs to those who have perfect knowledge of Holy Writ. Therefore the like knowledge should be possessed by those who are placed in Orders, and to whom the aforesaid words are addressed.
Objection 3 : Further, no one is competent to read what he understands not, since to read without intelligence is "negligence,"* as Cato declares (Rudiment.). [*"Legere et non intelligere est negligere." The play on the words is more evident in Latin.] Now it belongs to the reader (which is the lower Order) to read the Old Testament, as stated in the text (Sent. iv, D, 24). Therefore he should understand the whole of the Old Testament; and much more those in the higher Orders.