There are a lot of verses in the New Testament that describe the Father, Son, and Holy Ghost as one and much of "Christianity" misinterpret those verses to mean one person with some weird split personality type thing where they are 3 personalities in one person when the oneness is simply meant to be one in purpose and a unity of blessings. For example a board of directors of a company may have 15 directors but they form one board and they are one in wanting the best for the company. The oneness of the Godhead is meant in that kind of way This was clearly taught by Christ when He prayed to Heavenly Father for His 12 apostles and those that believe on their words:
John 17:
18 As thou hast sent me into the world, even so have I also sent them into the world.
19 And for their sakes I sanctify myself, that they also might be sanctified through the truth.
20 Neither pray I for these alone, but for them also which shall believe on me through their word;
21 That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me.
22 And the glory which thou gavest me I have given them; that they may be one, even as we are one:
23 I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me.