God is one. How can one speak of the Father the Son and the Holy Spirit?

THE BIBLE says

"Hear, O Israel: the LORD our God, the LORD is one!"

(Deut.6:4)

JESUS says

"Before Abraham was born, I am!"

(John 8:58)

"I and the Father are one."

(John 10:30)

"When the Counsellor comes, whom I will send to you from the Father,

the Spirit of truth who goes out from the Father, He will testify about Me."

(John 15:26)