What Is the Trinity?

While reading the Bible, I saw that Jehovah is God in certain parts and that Jesus is God in other parts. Are the two different Gods?
No. God appears in each age with a different appearance and a different name. In the age of the Father, God’s name was Jehovah; in the age of the Son, He came in the name of Jesus; and in the age of the Holy Spirit, He came in the new name of Jesus (cf. Revelation 3:12). All three of them are the same one God. So, the Trinity means that God the Father, God the Son, and God the Holy Spirit are not different but one and the same God.
God the Father is a father, and God the Son is a son. Then, how can They be one God?
It is easy to understand if you think Almighty God the Father performed three different roles. In each age, God came with a different name and a different role to save us.

For to us a child is born, to us a son is given, and the government will be on his shoulders. And he will be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace. Isaiah 9:6

In the above prophecy, “a child” and “a son” refer to Jesus who would be born as a human being in this world. It is written here that Jesus is a son, Mighty God, and Father. What does this mean? Although Jesus came as a man just like us, He is fundamentally God the Father.

But I’m still a little confused why Jesus is God the Father, because I heard so many times that Jesus Christ is the Son of God.
In many places of the Bible, it is written that Jesus is God.

Your attitude should be the same as that of Christ Jesus: Who, being in very nature God, did not consider equality with God something to be grasped, but made himself nothing, taking the very nature of a servant, being made in human likeness. Philippians 2:5–7

Theirs are the patriarchs, and from them is traced the human ancestry of Christ, who is God over all, forever praised! Amen. Romans 9:5

Although Jesus is God in nature, as He was born in the flesh on the earth, He is called the Son of God. God came to the earth in the position of a son, and He Himself set an example for us to know what we, God’s sons and daughters, should do to receive salvation. However, the fact that Jesus is in very nature God remains true.

Then, are Jesus and the Holy Spirit one and the same, too?
Of course, They are.

… But if anybody does sin, we have one who speaks to the Father in our defense—Jesus Christ, the Righteous One. 1 John 2:1

“The one who speaks in our defense” is parakletos in Greek, which means counselor or helper. In other words, Jesus is our Counselor (parakletos). In the Gospel of John, however, the Holy Spirit is the Counselor (Parakletos).

But the Counselor, the Holy Spirit, whom the Father will send in my name, will teach you all things and will remind you of everything I have said to you. John 14:26

Our Counselor is Jesus; and the Holy Spirit, too, is the Counselor. This means that Jesus and the Holy Spirit are one and the same God.

God the Father and God the Son Jesus are the same One, and God the Son Jesus and God the Holy Spirit are the same God. That means God the Father and God the Holy Spirit are one and the same, right?
Yes, that’s correct.

… but God has revealed it to us by his Spirit. The Spirit searches all things, even the deep things of God. For who among men knows the thoughts of a man except the man’s spirit within him? In the same way no one knows the thoughts of God except the Spirit of God. 1 Corinthians 2:10–11

No matter how many close friends you have, they cannot know your thoughts but only you can, right? Likewise, no one knows God’s thoughts except God Himself. And it is written here that the (Holy) Spirit searches all things, even deep things of God. That means God the Holy Spirit is God the Father.

Though it’s a little difficult, I think I’m understanding it.
In order to understand the Trinity better, think about the transformation of water. When water, which is liquid, freezes, it becomes ice which is solid. When you boil the liquid water, it becomes vapor which is gas. Water, ice, and vapor are different in form and name, but their essence is the same H₂O.

Likewise, God the Father, God the Son, and God the Holy Spirit work in a different appearance and a different name in each age, but fundamentally they are one and the same God.

Now that I hear the example, I can clearly understand what the Trinity means.
Surprisingly, there are still many Christians who don’t know about God in Trinity and how God carries out the redemption work, though they claim to know the Trinity. Brother, please remember that God the Father, God the Son, and God the Holy Spirit are one and the same God, and make sure to participate in God’s redemption work.