From Scripture. This answer is plainly backed by the text of Scripture.
Think about it this way. If one or two people saw a talking snake and told others, who would believe them? That question helps answer this one.
God works through miracles. Someone walked on water. A man was taken up alive in a whirlwind with chariots of fire. A large body of water split open to make a path for about a million people. The whole earth was flooded. We have not seen any of these things. But witnesses tell us about them in the Word. Do we believe it? Scripture says only Adam and Eve saw and spoke with the serpent. The rest of us have to take it on faith.
Remember, the Most High never said His goal was to put on a show for everyone until they believe. His Word shows that He reveals Himself to a certain group, usually a small one. Then He uses that group to spread His message to many others. For example, Israel was called the smallest of all nations (Deuteronomy 7:7), yet He showed Himself only to them at Mount Sinai. The Messiah Himself was shown “Not to all the people”, but to a chosen few (Acts 10:40-41). He is looking for people who will live worthy of His calling. He wants them to trust the testimony we have been given, instead of each of us seeing the miracles for ourselves (John 20:29).
Answered by Taught of Yah