Are you asking why it became expressly forbidden according to sacred texts to name the deity?

In the Hebrew Bible itself, the commandment against "taking God's name in vain" is directed against abuse of the name of God, not against any use. Since swearing by the name of God was used to attest the truth of one's testimony, this commandment might be interpreted as a commandment against perjury, or it might be a proscription against the abuse of the sacred name of god in the form of blasphemy or ritual magic. Regardless, there are numerous examples in the Hebrew Bible and a few in the New Testament where God's name is called upon in oaths to tell the truth or to support the truth of the statement being sworn to, and the books of Daniel and Revelation include instances where an angel sent by God invokes the name of God to support the truth of apocalyptic revelations.

Based on this commandment, Second Temple Judaism by the Hellenistic period developed a taboo of pronouncing the name of God at all, resulting in the replacement of the Tetragrammaton (YHWH) by "Adonai". This taboo then became generalized in later sects of Judaism and Christianity but not universally so.