That which came from the Apostles themselves, repeated orally and written down later, has the same Apostolic authority, as St. Paul himself said: "So then, brethren, stand firm and hold to the traditions which you were taught by us, either by word of mouth or by letter" (2 Thess. 2:15).
The early Fathers -- even when they are not directly quoting the words of the Apostles-- are a valuable resource, especially in interpreting Scripture correctly.
They were often native speakers of the languages in which the Scriptures were written, or recognized by their contemporaries both as men of piety and as scholars, much closer to the Biblical times, mindset, and culture than we are.
For a comparison: suppose that there are some ambiguities of language or interpretation in the reading of Geoffrey Chaucer (Canterbury Tales.) It would be more relevant to look for commentaries from the 15th century, from near-contemporaries, than from a scholar whose knowledge of the English language and English culture is almost all from the 19th and 20th centuries.
The Fathers were highly respected by the believers in their day (which is why their writings have been carefully preserved from their day until now); the earliest ones were disciples and 1st-generation successors of the Apostles themselves; and they offer a rich insight into the thinking and practices of the faithful of early Church.
BTTT.
Just two stories from my past:
(1) Many years ago, Fr. F. Laisnay of the SSPX (spelling deliberately wrong here) told me that the Bible had to be interpreted though the FOTC (Fathers of the Church).
(2) Just a few years ago, a Lutheran friend wanted to feel OK about infant baptism for his children. He didn’t find examples in the Bible, so he felt much better about it after he read examples in the FOTC.
Anyway, I liked both of your answers.
Thanks.
P.S. Trivia: I’ve heard that the Bible could be completely rewritten from quotes in the FOTC if all the Bible manuscripts were ever to be lost. (Not that that is probable.)