Trinity is the term by which is expressed the Christian belief that there are three persons in one God. Christian doctrine holds that a) there is only one God, one divine nature and being. b) This one divine being is tripersonal, that is, three persons in one God, designated as God the Father, God the Son, and God the Holy Spirit. c) These three persons are joint partakers of the identical nature and majesty of God. While this doctrine is a preeminent mystery of revelation, the believed revealed nature of God, transcending human or finite comprehension, it is considered essential to the understanding of the scriptures.
Even though the Trinity doctrine is implicit rather than explicit in the Old Testament, it is believe that with the accompanying knowledge of the New Testament, evidence of the Trinity can be found in the Old Testament (e. g., Numbers 6:24-26; Isaiah 6:3; 63:9, 10 the sanctity of the symbolical number three-the plural form of Elohim, also places in which the deity is spoken of as conversing with himself). This is thought to be in accordance with the gradual development of revealed truths in other particulars. However, the Hebrew religion of the Old Testament is emphatically monotheistic; a principle reason for this is thought to have been that such religious rigidity was that it provided a safeguard against polytheism.
The Celtic trinity knot is a very simple, but powerful symbol and very suitable for a tattoo. It is a triangle knot, the 3 corners have various meanings:
