If you maintained the same position then as you do now - that you don't accept any new revelations or interpretations outside what you have already received - then if you lived at the time of Christ you would have rejected Him and all the New Testament writings - since they would be new revelations and interpretations to you
The Bible canon closed with the book of Revelation 1,900 years ago, therefore there is no new revelations.
A closed canon also implies that there are no apostles or prophets today who are receiving new messages from God. The church is gifted with teachers and preachers of the Word today, but anyone who claims a new revelation from God, proffers his or her message as divinely inspired, or assumes authority on par with the Bible is leading people astray.
If you maintained the same position then as you do now - that you don't accept any new revelations or interpretations outside what you have already received - then if you lived at the time of Christ you would have rejected Him and all the New Testament writings - since they would be new revelations and interpretations to you.
The coming of the Messaih was prophecised from the beginning. The whole OT is about His coming.
Jeremiah 31 also tells us that there will be a new covenant. Verse 31 “Behold, the days are coming, declares the Lord, when I will make a new covenant with the house of Israel and the house of Judah.
Your argument is invalid, and you make assumptions that are simply not true.
The Messiah was promised, the Messiah came, the Messiah was sacrificed, the Messiah risen, the Mesaiah revealed to us the future.
God has placed in the closed canon of Scripture everything we need to know about Himself, and about who we are, how we ought to live.
Proverbs 30:5-6 “Every word of God is flawless; he is a shield to those who take refuge in him. Do not add to his words, or he will rebuke you and prove you a liar.”