"By the Trinity of God we mean His tri-personal existence as Father, Son, and Holy Spirit - three distinct Persons in one God.
1) The Father is recognized as God (1 Peter 1:2) and is all the fullness of the Godhead invisible (John 1:18).
2) The Son is recognized as God (Hebrews 1:8) and is all the fullness of the Godhead manifested in the flesh ((John 1:14).
3) The Holy Spirit is recognized as God (Acts 5:3,4) and is all the fullness of the Godhead acting upon man, convicting him of sin (John 16:7-11) and guiding the believer into all truth (John 16:12-15).
4) The doctrine of the Trinity is not explicit in the Old Testament, but is rather implied, "Then God said, Let Us make man ..." (Genesis 1:26).
5) The doctrine of the Trinity is revealed in the New Testament. In Matthew 3:16, 17 we have Christ being baptized in water, the Father speaking from heaven, and the Holy Spirit descending as a dove. We are to baptize in the "name (not names) of the Father and the Son and the Holy Spirit." (Matthew 28:19).
6) Even creation implies the doctrine of the Trinity. In creation, we have space, matter and time in one creation. In space, we have length, breadth, and height in one space. In matter, we have energy, motion, and phenomenon in one substance. In time, we have past, present, and future in one time. In man we have body, soul, and spirit in one man. (1 Thessalonians 5:23).
7) In the Holy Trinity, we have Father, Son, and Holy Spirit in one God."
I pray this helps you to be able to give an answer to anyone about what you believe and why you believe it. I also hope this blesses you and encourages you to love, praise, thank, and pray to each person of the Holy Trinity.
(This is From : Bible Foundation Course Lesson 02- 06)
