The Trinity doctrine basically says that there is one Deity. The Father is Eloah, the Son is Eloah, and the Holy Spirit is Eloah. Hence, you get Eloah the Father, Eloah the Son, and Eloah the Holy Spirit. Three persons, but not three beings, but they jointly make up one Eloah. But each of the three is not the other. However, each is co-equal, co-eternal, and co-powerful. Eloah, in essence, is perceived as an entity made up of three personalities. The following old sketch called the "Shield of the Trinity" has been commonly used by to explain the Trinity doctrine:
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WLC DISCLAIMER: WLC does NOT believe in, uphold, or teach the TRINITY doctrine, but attempts only to explain its definition in the above article.