Is the Trinity in the Bible?
making sure we are all on the same page when it comes to what the doctrine of the Trinity involves. This is important because a lot of people assume that if they see a passage in the Bible which mention God, Christ, and the Holy Spirit all in one verse or one passage (e.g., Matthew 28:19-20), or at least they infer the presence of all three in one passage, as Christian readers have long done, even in rather unexpected places – for example, the very first chapter of the Bible! (Genesis 1:1-2, 26) – that this is the doctrine of the Trinity. But no, it is not.
The Trinity is much more than just having these three beings named at once. It’s a distinct way of understanding the three in themselves and in relation to one another. The doctrine states that the Godhead is made up of three distinct persons: the Father, the Son, and the Holy Spirit. These are not all the same person. They are three people. Moreover, each of these three persons is fully God. In fact, they are all equal to each other (no one is “superior” to the others) and they are made up of the “same substance.” And together, the three of them are the one God. That’s the doctrine. These three are one.
It is easy for non-Christians to laugh and call it nonsense. But the people who came up with the doctrine were not idiots. Most of the serious theologians who developed the full logic in the fourth and fifth centuries were deep thinkers and highly trained in philosophy. Many of them were smarter, frankly than you and me. Or at least me. They understood that the doctrine did not pass the normal standards of logic. And that applying those standards to it could not yield sense. If one of them were alive today and you suggested they were an idiot for believing an obviously contradictory view, they may well ask you how well versed you were in quantum physics.
https://ehrmanblog.org/is-the-trinity-in-the-bible/