2 Timothy 3:16 All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, 17 so that the servant of God may be thoroughly equipped for every good work.

Here’s where the fun begins. What scriptures is he talking about here? The Gospels? Revelation? We can look at the prior verse to get an idea.

15 and how from infancy you have known the Holy Scriptures, which are able to make you wise for salvation through faith in Christ Jesus.

There’s a case to be made that early books of the NT were already being considered scripture; however, the only scripture available at the birth of Timothy is the Old Testament.