Usually, the testimony of two or more witnesses already serves as evidence.
It serves as evidence that two or more witnesses hold the same belief.
Anecdotal evidence - or eyewitness testimony, for that matter - is evidence. It's just a rather weak form of evidence. That is why courts of law usually look for better evidence, especially physical evidence.
If two witnesses claim they saw a person being murdered, the police are very likely to investigate their claims. But if there is no body to be found, no missing person who matches the description of the supposed victim, conflicting evidence from other witnesses, etc., then it is unlikely that the police will pursue the claims of the witnesses for long. Instead, they will say: we will stop actively investigating this report, until and unless new evidence comes to light. In the meantime, nobody will be prosecuted for murder.
And here are the testimonies of billions of people on all continents, and at all times, but for you they are not evidence.
They are evidence of what billions of people believe. But, like the police, I will need something more than that before I accept that any god is real.
It's one thing to talk vaguely about gods in general, but of those billions of people on all continents who believe in gods, lots of them believe in different and incompatible gods. Believers in Yahweh don't accept Krishna. Believers can't even agree on
how many gods there are, let along which ones are the ones that actually exist.
Well, then at least think about why people need God?
At least think about why people don't need God.
How are they different from you, atheists? Just don't say that they are all stupid and uneducated. Believe me, among them there are many scientists, doctors, and anyone whose knowledge is not inferior to yours, and even surpasses them.
Stupid isn't the whole explanation for why people believe in gods, obviously. On the other hand, studies tend to show that you're less likely to believe in gods when you're smarter and/or more highly educated.
People can become convinced of all kinds of things that aren't true for bad reasons. In the case of religion, the number one culprit is consistent indoctrination at a very young age.
Smart people who
already believe dumb things often find clever ways to justify their beliefs to themselves. They are also prone to ignoring or dismissing evidence that tends to refute their beliefs. In one way, it's harder for a smart person to accept they are mistaken, because they are probably accustomed to being right about many things. It's easier to assume that other people are mistaken, when you don't critically examine your own beliefs.