Is it true that 2 Timothy 3:16-17 refers only to the Old Testament since there was no New Testament yet?

In actuality, some of the New Testament was already in existence by the time Paul wrote 2 Timothy.  Paul likely wrote 2 Timothy not long before his death, which many believe to be around A.D. 62-64 when he was beheaded by Nero according to tradition.  Since Paul spoke of his upcoming death to Timothy in that book, one can reasonably infer that all of Paul’s letters — which make up the majority of the New Testament books — had already been written by this time.  Indeed, scholarship holds most of them to have been written in the A.D. 50’s.  Peter, writing his own last book before his death, spoke of Paul’s writings in such a way to make it clear that he knew his Christian readers would be familiar with them, and also referred to them as “Scripture” (2 Pet. 3:15-16).  Additionally, Paul himself quoted the Gospel of Luke in his first letter to Timothy and cited it as “Scripture” (1 Tim. 5:18; cf. Lk. 10:7).  Some believe that the book of James might have been one of the earliest New Testament books to have been written, possibly in the forties or fifties A.D.  It is possible that after Paul’s death only John’s writings (the Gospel of John, 1-3 John, and Revelation) would be the last books of the New Testament to be written, and they were written a few decades later in the A.D. 90’s.

To sum up, 2 Timothy 3:16-17 certainly applies to the Old Testament…but not only to the Old Testament.  It also applies to the New Testament.