THE TRINITY
The pagans believed in a Triad of gods. They were polytheists. That means they believed in three main gods (Triad) who were completely separate beings. And they ruled over the rest of the gods.
The Trinity is 1 God with three persons-The Father, The Son, and The Holy Spirit that are equal in essence and nature as One God. And they rule over No other gods as there's only one God. A triangle has three point but it is still One triangle.
We have One-The Trinity. And the Bible clearly states in the Trinity, so it's not from "outside pagan religions."
For example, Peter refers to the saints who have been chosen "according to the foreknowledge of God The Father." (1 Peter 1:2) when Jesus made a post resurrection appearance to Thomas, the disciple worshipfully responded by addressing Him, "My Lord and MY GOD." (John 20:28) The Father also said of the Son, "Your throne O God, is forever and ever." In Acts 5:3-4, we are told that lying to the Holy Spirit is equivalent to lying to God. Peter said,"Ananias, why has satan filled your heart to lie to the Holy Spirit,,, You have not lied to men but to God."
Besides being called God, each of the three persons are seen on different occasions to possess the attributes of deity. Note the following examples:
All three persons possess the attribute of omnipresence:
The Father (1 Kings 8:27)
The Son (Matthew 28:20)
The Holy Spirit (psalm 139:7)
All three have the attribute of omniscience:
The Father (psalm 147:5)
The Son (John 16:30)
The Holy Spirit (1 Corinthians 2:10)
All three have the attribute of omnipotence:
The Father (Psalm 135:6)
The Son (Matthew 28:18)
The Holy Spirit (Romans 15:19)
Holiness is ascribed to each of the three persons:
The Father (Revelation 15:4)
The Son (Acts 3:14)
The Holy Spirit (Romans 1:4)
Eternity is ascribed to each of the three persons:
The Father (Psalm 90:2)
The Son (Micah 5:2, John 1:4)
The Holy Spirit (Hebrews 9:14)
Each if the three persons is described as the Truth:
The Father (John 7:28)
The Son (Revelation 3:7)
The Holy Spirit (1 John 5:6)
Each of the three is called Lord (Luke 2:11, Romans 10:12, 2 Corinthians 3:17) Each is called Everlasting (Romans 16:26, Hebrews 9:14, Revelation 22:13) Each is called Almighty (Genesis 17:1, Romans 15:19, Revelation 1:8)
And each is called Powerful (Jeremiah 32:17, Zechariah 4:6, Hebrews 1:3)
Can any one other than God have the Attributes of God?
In addition to having the attributes of deity, each of the three persons were involved in doing the works of deity. For example, all three were involved in the creation of the world:
The Father (Genesis 2:7, Psalm 102:25, 1 Corinthians 8:6)
The Son (John 1:3, Colossians 1;16, Hebrews 1:2)
The Holy Spirit (Genesis 1:2, Job 33:4, Psalm 104:30)
They were also involved in the incarnation and resurrection but I won't go into those verses as I think these are good for now.
Also to mention, that the pagans taught the concept of a flood that killed most of humankind and the concept of a messiah like figure named Tammuz who was allegedly resurrected. Are those concepts false just because pagans taught remotely similar accounts?
And if you still don't understand the Trinity, does it mean it's not True? I mean do you think it is possible for human beings to know everything about God? If yes, please explain Isaiah 55:8-9, Romans 11:33, and 1 Corinthians 13:12.
We should not reject a doctrine simply because we cannot fully comprehend it. Especially since it's in the Bible