In the modern West, people often consider ideas that are new, novel, and more recently discovered through the most up to date studies and methodologies to carry the most weight. In the Buddhist East, however, this is not the case. It is common among Asian Buddhists to consider the fact that Siddhartha Gautama (the man known as 'the Buddha') lived and taught around 500 years before Jesus walked the earth to be an argument in favor of the truth and value of Buddhism over Christianity. These cultures generally see wisdom that is more ancient and time-tested to be more venerable and more likely to be true. The truth is that neither novelty nor ancient origin are, in fact, good arguments in and of themselves for the truth of an idea or teaching. Still, it is worthwhile to note for the sake of Buddhist friends that the Christian gospel is actually a more ancient wisdom than Buddhism.

The Prophets and the Ancient Gospel
While it is a plain fact of history that the founder of Buddhism did indeed teach centuries before Jesus' earthly ministry, this is not the full picture. The gospel was preached by the prophets of God even earlier than that. Long before Siddhartha Gautama was born in India, the prophet Isaiah proclaimed that:

The Messiah would be God in the flesh (Isaiah 9:6)
He would be born of a virgin and called "God with us" (Isaiah 7:14).
He would be sinless, but would die for the sins of others and would rise from the dead unto glory, power, and victory (Isaiah 53).
Salvation would be found in repentance and quiet trust (Isaiah 30:15)
The repentant will be redeemed, and those who remain in their sins will be judged (Isaiah 1:27-28).
This is the Christian gospel, preached not only before the coming of Jesus Christ but also before the life of Buddha as well. Jesus did not come to introduce this reality, but to fulfill it.

This is why the apostle Paul writes:

"Now I make known to you, brethren, the gospel which I preached to you, which also you received, in which also you stand, by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain. For I delivered to you as of first importance what I also received, that Christ died for our sins according to the Scriptures, and that He was buried, and that He was raised on the third day according to the Scriptures," (1 Corinthians 15:1-4).

Note the Paul does not merely report that these things occurred, but that they occurred "according to the Scriptures." The gospel is that which was written about long before and later fulfilled in Jesus Christ. Jesus Himself taught us this in saying:

"'These are My words which I spoke to you while I was still with you, that all things which are written about Me in the Law of Moses and the Prophets and the Psalms must be fulfilled.' Then He opened their minds to understand the Scriptures, and He said to them, 'Thus it is written, that the Christ would suffer and rise again from the dead the third day, and that repentance for forgiveness of sins would be proclaimed in His name to all the nations, beginning from Jerusalem. You are witnesses of these things,'" (Luke 24:44-48)

We can look at Balaam's prophecy in the time of Moses of the victorious star that would come forth from Jacob (Numbers 24:15-19). We can go back even further to Jacob's prophecy of Shiloh to come (Genesis 49:10). We can trace the message earlier still, to the time of Abraham and Isaac where it was foretold that, just as God had provided a ram in Isaac's place, God would one day again provide a substitute for his people on the holy mount (Genesis 22:13-14). Indeed, we can look back to the beginning of time at man's very first sin and see the promised seed of the woman would one day crush the serpent (Genesis 3:15). In all ages, it was foretold that the promised one would come. The gospel is as old as sin and suffering itself. There is no wisdom and no hope more ancient than this.

The Commandments
There is a well-known story in the gospels in which Jesus is approached by a wealthy man desiring to inherit eternal life. Jesus questions the man on his keeping of the commandments, to which the man retorts by asking Jesus to which commandments he is referring. Jesus replied:

"You shall not commit murder; you shall not commit adultery; you shall not steal; you shall not bear false witness; you shall honor your father and mother; and you shall love your neighbor as yourself," Matthew 19:18-19

If you tell this much of the story to a Buddhist monk, he will likely smile in agreement. While the terminology of "eternal life" is quite the opposite of the Buddhist hope, the commands listed here he would generally find quite familiar and agreeable. Five centuries before Jesus spoke these words to that young man, Buddha laid out the eightfold path to enlightenment and Nirvana. He taught that "right action" was necessary, which specifically included abstaining from killing, stealing, and adultery. He taught that right speech was necessary, which specifically included abstaining from deceit and false witness. The Buddhist would see Jesus as merely affirming what Buddha had already established long before Him. But the Buddhist would be mistaken.

While there are certainly basic ethical teachings in Buddhism that are also found in Christianity, Christianity holds to them based on sources far older than the time of Siddhartha Gautama. Six hundred years before Buddha ever spoke a word, God revealed all of these commandments to Moses. They were written down in the Torah and expounded upon in the prophets and other biblical writings all before Buddha was ever born. If ancient origins give one faith greater claim to these commands than the other, then Christians certainly hold the stronger claim.

The Manuscripts
It is also interesting to note that the earliest fragments of manuscripts reporting the words of Buddha that we still have today are from around the first or second century AD.1 This is roughly the same period from which our earliest fragments of the gospels come. Our earliest approximately complete manuscript of a comprehensive collection of Buddha's teachings is from the middle ages, some 2,000 years after Buddha actually lived.2

By comparison, the first manuscript preserving nearly all of the text of all four gospels is a copy from about 220 AD.3 The reality is that we possess today a far more ancient witness to the words of Jesus than to those of Buddha. Buddha may have lived at an earlier date than Jesus earthly life, but we do not have a present witness to his words that is more ancient than the time of Jesus, or even than the time of the earliest Christian manuscripts.

Conclusion
The mere age of an idea does not make it true or false. While Buddhist cultures do tend to put great weight on what is old and time-tested over what is new and think that this gives Buddhism greater authority than Christianity, this assumption is flawed. First of all, it is flawed on the obvious grounds that older ideas are not always better than newer ones. Buddha himself came offering new ideas his culture had never heard. In doing so, he openly corrected the ancient traditions that were then prevalent around him. If the older idea is always better, Buddhism should never have been taken seriously in the first place.

Second of all, it is flawed because it wrongly assumes that the Christian gospel is less ancient than Buddhism simply because Jesus physically walked the earth at a later date than when Buddha lived. As we have seen, the manuscript witness to the teachings of Jesus are older than those of Buddha The teachings of Jesus are rooted in commands and wisdom revealed long before Buddha lived. The Christian gospel fulfilled in Jesus was promised by God for as long as men have lived and was written down by His prophets centuries before Buddha was ever born. If one does insist on giving special weight to what is ancient and time-tested over what is more recent, the Christian gospel ought certainly to be the more greatly revered of these teachings.

https://carm.org/does-it-matter-that-buddha-came-long-before-jesus?fbclid=IwAR3e_jpyrrdeq2vr-WZNtWHHwAXE9YX_NVIi5Y2xaXLlNvPnoOXtvLsElZc