Jaroslav Pelikan writes about the common “plunder the Egyptians” attitude of the church fathers:
The attitude of the church fathers toward classical thought contained a somewhat analogous judgment of its historic role. “Whatever things were rightly said among all men,” wrote Justin, “are the property of us Christians.” Christianity laid claim to all that was good and noble in the tradition of classical thought, for this had been inspired by the seminal Logos, who became flesh in Jesus Christ. This meant that not only Moses but Socrates had been both fulfilled and superseded by the coming of Jesus.
I’d add that as Classical Protestants, this can be our attitude towards the riches we can find in Roman Catholic and Eastern Orthodox writings. Not all of their thoughts are dross, after all, and the careful reader can harvest both good and bad from them, or any other baptized Christian.