The Trinity is one God existing in three Persons. Understand that this is not in any way suggesting three Gods. Keep in mind when studying this subject that the word “Trinity” is not found in Scripture. This is a term that is used to attempt to describe the triune God—three coexistent, co-eternal Persons who are God. Of real importance is that the concept represented by the word “Trinity” does exist in Scripture. The following is what God’s Word says about the Trinity:
There is one God (Deuteronomy 6:4; 1 Corinthians 8:4; Galatians 3:20; 1 Timothy 2:5).
The Trinity consists of three Persons (Genesis 1:1, 26; 3:22; 11:7; Isaiah 6:8, 48:16, 61:1; Matthew 3:16-17, 28:19; 2 Corinthians 13:14). In Genesis 1:1, the Hebrew plural noun "Elohim" is used. In Genesis 1:26, 3:22, 11:7 and Isaiah 6:8, the plural pronoun for “us” is used. The word "Elohim" and the pronoun “us” are plural forms, definitely referring in the Hebrew language to more than two. While this is not an explicit argument for the Trinity, it does denote the aspect of plurality in God. The Hebrew word for "God," "Elohim," definitely allows for the Trinity.
In the New Testament, Jesus speaks to the Father about sending a Helper, the Holy Spirit (John 14:16-17). This shows that Jesus did not consider Himself to be the Father or the Holy Spirit. Consider also all the other times in the Gospels where Jesus speaks to the Father. Was He speaking to Himself? No. He spoke to another Person in the Trinity—the Father.