So far no one has answered the question. Even IF the early Church was not the Catholic Church of today how do I answer the question using scripture alone?
If an outside authority in the second and third century told us what is inspired and said there can only be 27 books then how can scripture be our only authority? Why should I trust this early Church to say that Matthew the apostle wrote Matthew and that it is the inspired word of God.
Here are the questions again. Can anyone answer them using scripture as our only authority?
How do we know that Matthew, Mark, Luke and John wrote their Gospels? Also how do we know that Luke wrote Acts and it is inspired scripture?
From Scripture alone who was Mark and Luke? They clearly were not apostles so why do we consider them as being inspired authors?
None of the 27 books claim to be the inspired word of God so why do we believe they are inspired from scripture alone.
From scripture alone why is the book of Hebrews in the bible, who wrote it and why is it considered inspired?
Scripture never says how many books should be in the New Testament. From scripture alone why are there only 27 books and not more or less?
Scripture doesn't confirm these letters Matthew, Mark and Luke.
Now John can be with these verses and the entire book identifies him in several places.
John 21:20 Then Peter, turning about, seeth the disciple whom Jesus loved following; which also leaned on his breast at supper, and said, Lord, which is he that betrayeth thee?
24 This is the disciple which testifieth of these things, and wrote these things: and we know that his testimony is true.
Luke and Acts have the same author based on Acts 1:1 The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach,
Luke 1: 2 Even as they delivered them unto us, which from the beginning were eyewitnesses, and ministers of the word;
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,
4 That thou mightest know the certainty of those things, wherein thou hast been instructed.
Here is Mark:
Acts 12:12 And when he had considered the thing, he came to the house of Mary the mother of John, whose surname was Mark; where many were gathered together praying
24But the word of God grew and multiplied.
25And Barnabas and Saul returned from Jerusalem, when they had fulfilled their ministry, and took with them John, whose surname was Mark.
Here is Luke:
Colosians 4: 13For I bear him record, that he hath a great zeal for you, and them that are in Laodicea, and them in Hierapolis.
14Luke, the beloved physician, and Demas, greet you.
15Salute the brethren which are in Laodicea, and Nymphas, and the church which is in his house.
Here are Mark and Luke:
2 Timothy 4:11 Only Luke is with me. Take Mark, and bring him with thee: for he is profitable to me for the ministry.
Hebrews is filled with scriptural teachings and sound doctrine. Chapter 1: begins
1 God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets,
2 Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds
With Spiritual truth, it references Old Tesatament events and New Testament teachings. Based on way it is written most of the text is similar to Pauls although some fit Apollos writting. The bottom line it contains history and instruction on thing God.
Even if Matthew Mark and Luke didn't write these books trust what scripture says because it is the fianl authority and since we know John wrote his Gospel and many parts of John match up to things contained in Matthew, Mark and Luke we can trust them to be accurate. Since the same writer wrote Luke and Acts then Acts can be trusted.
