Westminster Shorter Catechism Q&A 6

Q. 6. How many persons are there in the godhead?
A. There are three persons in the Godhead; the Father, the Son, and the Holy
Ghost; and these three are one God, the same in substance, equal in power
and glory.

Question 6 tells us that God exists in three persons. This is one way in which God is different from human beings. A human is one being and one person. There is one of you and you are only one person. There is one God, but He is three persons.
Do you find that hard to understand? You are not alone! The wisest Christians and the best Bible students of the church have never been able to fully understand how God can be one God in three persons.
Remember that God is infinite. He has no limits. Human minds are finite and limited. We can only go so far with our limited minds in understanding the limitless God.
Over and over again, the Bible insists that there is only one God. At the same time, the Bible tells us that there are three persons – Father, Son, and Holy Spirit – each of whom is God.
We must believe what Scripture requires us to believe, even when we cannot fully
understand it.
Please read Job 11:7-8