Catholics tend to maintain their differences between oral tradition and written scripture at all costs, it is the basis of Catholicism that a lot of their traditions come from oral teaching passed over the centuries. They have to argue this way because much of their doctrine isn't in scripture. The same is true of Muslims where the Quran is considered oral tradition. The extra-biblical writings of the Catholic church do not claim inspiration per se.
Roman Supremacy (the word Rome isn't in the Gospels)
The Papacy (The word papacy isn't in the Gospels)
Catholic name (The word Catholic isn't in the New Testament, just a root used differently)
Celibacy (borrowed from Romes praetorian priests and Vestal virgins)
Infant Baptism (No actual examples in scripture, household didn't imply infants)
Original Sin
Cardinals
Gentiles Giving Scripture
Separated Priesthood
Three offices Bishop-Presbyter-Deacon
Separation of saints from the living saints
All of these are from so called Oral tradition. Plus, there are more.
In 2 Timothy 4 Paul tells Timothy to preach the Word, be instant in season and out of season. Most church groups believe this "Word" is contained in scripture, but Catholics tend to make this about Oral traditions, they claim the New Testament scriptures weren't given yet. In their view 2 Timothy 3:16 is a reference to Old Testament scripture only.
Is this true??????????No.
2 Timothy 3:16 includes New Testament scriptures. At the time 3 of the gospels were finished, possibly all. Plus the church epistles of Paul were completed. It also appears Peters epistles were finished as well. The book of Hebrews and James are said to be written before 50 ad.
The date of 2 Timothy is generally 67ad and all the books mentioned above were finished by 65ad according to many scholars. Some letters like I,II,III John have dates ranging from 40ad to 100ad. Exact dates are difficult to discern.
All scripture is generally and almost universally believed to be finished by 100ad. Yet, that doesn't mean the complete works of Jesus werent finished much earlier. Some believe John's gospel was finished before 65 ad. Some believed as early as 40ad.
Luke says something interesting concerning his gospel of Luke.
Acts 1:1
The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach,
The Greek word "began" doesn't mean to begin but not finish, it means to start from the beginning and discuss orderly. It can mean sustained till completion. Since it says "I made" it shows completion.
These are the complete works and sayings of Jesus as taught by the apostles. These aren't taught as Oral tradition, but as a student of the apostles he writes what he knows they said.
He doesn't leave anything out they said to him. So there is no extra teaching we could call oral. Not from the apostles.
Luke is a list of things believed.
Luke 1:1
Forasmuch as many have taken in hand to set forth in order a declaration of those things which are most surely believed among us,
Luke 1:2
Even as they delivered them unto us, which from the beginning were eyewitnesses, and ministers of the word;
This is what the ministers of the word believed and delivered. Luke is a record of public teaching of the word. The oral and written are the same.
Luke 1:3
It seemed good to me also, having had perfect understanding of all things from the very first, to write unto thee in order, most excellent Theophilus,
These are "all things" from the very first, and orderly given.
Luke 1:4
That thou mightest know the certainty of those things, wherein thou hast been instructed.
Instructed here is past tense, it is the oral instruction itself. Luke writes this it seems as a miracle. A man not present at theophilus instruction, repeats exactly what was said to him.
So there is no distinction between oral and written, there were no extra biblical oral instruction. Scripture contained "all things meant to be remembered.
One might ask about all the hundreds of discussions with Jesus and miracles people saw not written? Well, there were personal memories people had they could pass to friends and family. I am sure many stories were passed, but not from apostles and prophets and scribes.
The early ministers stuck to processing the official necessary events and teachings as directed by the Holy Spirit. These other memories were meant to fade away and not be remembered.
1 Corinthians 13:8
Charity never faileth: but whether [there be] prophecies, they shall fail; whether [there be] tongues, they shall cease; whether [there be] knowledge, it shall vanish away.
All the memories and knowledge left out of the written version would cease to be remembered. So, there is no Catholic oral tradition. The scriptures are the record.
There are many verses showing that written and oral are the same. Oral can only be confirmed when inspired.
Joshua 1:8
let this book of the law be in your mouth...
Compared to "preach the word" it is the same.
Also, Catholics confuse past oral traditions with past history. Oral tradition can be untrue whereas past history is always true and always happened. Oral tradition can be backwards.
Scripture, because of inspiration, always gets it right. Catholics admit oral tradition is uninspired memories.